Hướng dẫn python bool to byte - bool python thành byte

Mục lục bài viết:

• Kiểu Boolean Python
  • Python Booleans làm Từ khóa
  • Python Booleans dưới dạng số
• Toán tử Boolean
  • Các nhà khai thác không có đầu vào
  • Toán tử không phải Boolean
  • Toán tử và Boolean
  • Toán tử hoặc Boolean
  • Các toán tử Boolean khác
• Toán tử so sánh
  • Bình đẳng và Bất bình đẳng
  • So sánh đơn hàng
  • Nhà điều hành là
  • Nhà điều hành trong
  • Các toán tử so sánh chuỗi
• Thử nghiệm Boolean trong Python
  • Không có giá trị Boolean
  • Các số dưới dạng giá trị Boolean
  • Chuỗi dưới dạng giá trị Boolean
  • Các loại khác dưới dạng giá trị Boolean
  • Ví dụ: Mảng NumPy
  • Toán tử và Chức năng
• Phần kết luận

Kiểu Boolean trong Python là một trong những kiểu dữ liệu tích hợp sẵn của Python . Nó được sử dụng để biểu thị giá trị chân lý của một biểu thức. Ví dụ, biểu thức 

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Trong hướng dẫn này, bạn sẽ học cách:

• Thao tác các giá trị Boolean với các toán tử Boolean
• Chuyển đổi Boolean sang các loại khác
• Chuyển đổi các loại khác sang Python Booleans
• Sử dụng Python Booleans để viết mã Python hiệu quả và dễ đọc

Kiểu Boolean Python

Kiểu Boolean trong Python chỉ có hai giá trị có thể có:

1. >>> lines="""\
   ... He took his vorpal sword in hand;
   ...       Long time the manxome foe he sought—
   ... So rested he by the Tumtum tree
   ...       And stood awhile in thought.
   ... """.splitlines()
   >>> sum("the" in line.lower() for line in lines) / len(lines)
   0.5
   

   8

2. >>> lines = """\
   ... He took his vorpal sword in hand;
   ...       Long time the manxome foe he sought—
   ... So rested he by the Tumtum tree
   ...       And stood awhile in thought.
   ... """
   >>> line_list = lines.splitlines()
   >>> "the" in line_list[0]
   False
   >>> "the" in line_list[1]
   True
   >>> 0 + False + True # Equivalent to 0 + 0 + 1
   1
   >>> ["the" in line for line in line_list]
   [False, True, True, False]
   >>> False + True + True + False
   2
   >>> len(line_list)
   4
   >>> 2/4
   0.5
   

   0

Không có giá trị nào khác sẽ có 

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>>

>>> type(False)

>>> type(True)

Của 

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Kiểu 

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>>

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> type(False)

>>> type(True)

Python Booleans làm Từ khóa

Python Booleans dưới dạng số

Toán tử Boolean

Các nhà khai thác không có đầu vào

>>>

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

>>> type(False)

>>> type(True)

>>>

>>> False = 5
  File "", line 1
SyntaxError: cannot assign to False

>>> type(False)

>>> type(True)

Của >>> lines = """\ ... He took his vorpal sword in hand; ... Long time the manxome foe he sought— ... So rested he by the Tumtum tree ... And stood awhile in thought. ... """ >>> line_list = lines.splitlines() >>> "the" in line_list[0] False >>> "the" in line_list[1] True >>> 0 + False + True # Equivalent to 0 + 0 + 1 1 >>> ["the" in line for line in line_list] [False, True, True, False] >>> False + True + True + False 2 >>> len(line_list) 4 >>> 2/4 0.5 6cả hai >>> lines = """\ ... He took his vorpal sword in hand; ... Long time the manxome foe he sought— ... So rested he by the Tumtum tree ... And stood awhile in thought. ... """ >>> line_list = lines.splitlines() >>> "the" in line_list[0] False >>> "the" in line_list[1] True >>> 0 + False + True # Equivalent to 0 + 0 + 1 1 >>> ["the" in line for line in line_list] [False, True, True, False] >>> False + True + True + False 2 >>> len(line_list) 4 >>> 2/4 0.5 0và >>> lines="""\ ... He took his vorpal sword in hand; ... Long time the manxome foe he sought— ... So rested he by the Tumtum tree ... And stood awhile in thought. ... """.splitlines() >>> sum("the" in line.lower() for line in lines) / len(lines) 0.5 8là >>> lines = """\ ... He took his vorpal sword in hand; ... Long time the manxome foe he sought— ... So rested he by the Tumtum tree ... And stood awhile in thought. ... """ >>> line_list = lines.splitlines() >>> "the" in line_list[0] False >>> "the" in line_list[1] True >>> 0 + False + True # Equivalent to 0 + 0 + 1 1 >>> ["the" in line for line in line_list] [False, True, True, False] >>> False + True + True + False 2 >>> len(line_list) 4 >>> 2/4 0.5 3.

Kiểu 

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>>

>>> True == 1
True
>>> False == 0
True
>>> True + (False / True)
1.0

>>> type(False)

>>> type(True)

Của 

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>>

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> type(False)

>>> type(True)

Để xem tại sao điều này hoạt động, bạn có thể chia đoạn mã trên thành các phần nhỏ hơn:

>>>

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Các 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

Vì 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

Toán tử Boolean

Toán tử Boolean là những toán tử nhận đầu vào Boolean và trả về kết quả Boolean .

Lưu ý: Sau đó, bạn sẽ thấy rằng các toán tử này có thể được cung cấp các đầu vào khác và không phải lúc nào cũng trả về kết quả Boolean. Hiện tại, tất cả các ví dụ sẽ sử dụng đầu vào và kết quả Boolean. Bạn sẽ thấy cách điều này tổng quát cho các giá trị khác trong phần về độ tin cậy .

Vì các giá trị Boolean trong Python chỉ có hai tùy chọn khả thi, 

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Như bạn sẽ thấy ở phần sau, trong một số tình huống, biết một đầu vào cho một toán tử là đủ để xác định giá trị của nó. Trong những trường hợp đó, đầu vào khác không được đánh giá. Đây được gọi là đánh giá ngắn mạch .

Tầm quan trọng của việc đánh giá ngắn mạch phụ thuộc vào từng trường hợp cụ thể. Trong một số trường hợp, nó có thể ít ảnh hưởng đến chương trình của bạn. Trong các trường hợp khác, chẳng hạn như khi cần tính toán nhiều để đánh giá các biểu thức không ảnh hưởng đến kết quả, nó mang lại lợi ích hiệu suất đáng kể. Trong những trường hợp khắc nghiệt nhất, tính đúng đắn của mã của bạn có thể phụ thuộc vào việc đánh giá ngắn mạch.

Các nhà khai thác không có đầu vào

Bạn có thể nghĩ về 

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Việc coi các giá trị Boolean trong Python như các toán tử đôi khi rất hữu ích. Ví dụ: cách tiếp cận này giúp nhắc nhở bạn rằng chúng không phải là các biến. Vì lý do tương tự mà bạn không thể gán cho 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Chỉ có hai giá trị Boolean trong Python tồn tại. Toán tử Boolean không có đầu vào luôn trả về cùng một giá trị. Bởi vì điều này, 

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Các >>> bool >>> bool = "this is not a type" >>> bool 'this is not a type' 30Boolean điều hành

Toán tử Boolean duy nhất có một đối số là 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Bảng này minh họa 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>>

>>> not True
False
>>> not False
True
>>> def print_and_true():
...     print("I got called")
...     return True
...
>>> not print_and_true()
I got called
False

Dòng cuối cùng cho thấy 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Bạn có thể tự hỏi tại sao không có toán tử Boolean nào khác nhận một đối số duy nhất. Để hiểu lý do tại sao, bạn có thể nhìn vào bảng hiển thị tất cả các toán tử Boolean về mặt lý thuyết có thể sử dụng một đối số:

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Chỉ có bốn toán tử khả thi với một đối số. Ngoài ra 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

• >>> bool
  
  >>> bool = "this is not a type"
  >>> bool
  'this is not a type'
  

  53: Vì toán tử này chỉ trả lại đầu vào của nó, bạn chỉ có thể xóa nó khỏi mã của mình mà không ảnh hưởng gì.

• >>> bool
  
  >>> bool = "this is not a type"
  >>> bool
  'this is not a type'
  

  54: Đây là một toán tử ngắn mạch vì nó không phụ thuộc vào đối số của nó. Bạn chỉ có thể thay thế nó bằng 

  >>> lines="""\
  ... He took his vorpal sword in hand;
  ...       Long time the manxome foe he sought—
  ... So rested he by the Tumtum tree
  ...       And stood awhile in thought.
  ... """.splitlines()
  >>> sum("the" in line.lower() for line in lines) / len(lines)
  0.5
  

  8và nhận được kết quả tương tự.

• >>> bool
  
  >>> bool = "this is not a type"
  >>> bool
  'this is not a type'
  

  56: Đây là một toán tử ngắn mạch khác vì nó không phụ thuộc vào đối số của nó. Bạn chỉ có thể thay thế nó bằng 

  >>> lines = """\
  ... He took his vorpal sword in hand;
  ...       Long time the manxome foe he sought—
  ... So rested he by the Tumtum tree
  ...       And stood awhile in thought.
  ... """
  >>> line_list = lines.splitlines()
  >>> "the" in line_list[0]
  False
  >>> "the" in line_list[1]
  True
  >>> 0 + False + True # Equivalent to 0 + 0 + 1
  1
  >>> ["the" in line for line in line_list]
  [False, True, True, False]
  >>> False + True + True + False
  2
  >>> len(line_list)
  4
  >>> 2/4
  0.5
  

  0và nhận được kết quả tương tự.

Không có toán tử nào khác có thể có với một đối số sẽ hữu ích.

Các >>> bool >>> bool = "this is not a type" >>> bool 'this is not a type' 58Boolean điều hành

Các 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Bảng này dài dòng. Tuy nhiên, nó minh họa hành vi tương tự như mô tả ở trên. Nếu 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Mã sau có đầu vào thứ hai có tác dụng phụ , in ra, để cung cấp một ví dụ cụ thể:

>>>

>>> def print_and_return(x):
...     print(f"I am returning {x}")
...     return x
...
>>> True and print_and_return(True)
I am returning True
True
>>> True and print_and_return(False)
I am returning False
False
>>> False and print_and_return(True)
False
>>> False and print_and_return(False)
False

Trong hai trường hợp cuối cùng, không có gì được in. Hàm không được gọi vì việc gọi nó không cần thiết để xác định giá trị của 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

Một ví dụ trong đó hành vi này có thể quan trọng là trong mã có thể tạo ra các ngoại lệ:

>>>

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

Trong hai trường hợp cuối cùng, không có gì được in. Hàm không được gọi vì việc gọi nó không cần thiết để xác định giá trị của 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

Một ví dụ trong đó hành vi này có thể quan trọng là trong mã có thể tạo ra các ngoại lệ:

Hàm >>> bool >>> bool = "this is not a type" >>> bool 'this is not a type' 85này được thừa nhận là ngớ ngẩn và nhiều linters sẽ cảnh báo về việc biểu thức này >>> bool >>> bool = "this is not a type" >>> bool 'this is not a type' 86là vô dụng. Nó phục vụ mục đích không thành công khi được cung cấp >>> def inverse_and_true(n): ... 1 // n ... return True ... >>> inverse_and_true(5) True >>> inverse_and_true(0) Traceback (most recent call last): File "", line 1, in File "", line 2, in inverse_and_true ZeroDivisionError: integer division or modulo by zero >>> False and inverse_and_true(0) False 4dưới dạng tham số vì phép chia cho >>> def inverse_and_true(n): ... 1 // n ... return True ... >>> inverse_and_true(5) True >>> inverse_and_true(0) Traceback (most recent call last): File "", line 1, in File "", line 2, in inverse_and_true ZeroDivisionError: integer division or modulo by zero >>> False and inverse_and_true(0) False 4không hợp lệ. Tuy nhiên, dòng cuối cùng không nêu ra một ngoại lệ. Do đánh giá ngắn mạch, hàm không được gọi, phép chia >>> def inverse_and_true(n): ... 1 // n ... return True ... >>> inverse_and_true(5) True >>> inverse_and_true(0) Traceback (most recent call last): File "", line 1, in File "", line 2, in inverse_and_true ZeroDivisionError: integer division or modulo by zero >>> False and inverse_and_true(0) False 4cho không xảy ra và không có ngoại lệ nào được nêu ra.

Ngược lại, 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Bảng này dài dòng. Tuy nhiên, nó minh họa hành vi tương tự như mô tả ở trên. Nếu 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Mã sau có đầu vào thứ hai có tác dụng phụ , in ra, để cung cấp một ví dụ cụ thể:

• >>>

• Trong hai trường hợp cuối cùng, không có gì được in. Hàm không được gọi vì việc gọi nó không cần thiết để xác định giá trị của 

  >>> bool
  
  >>> bool = "this is not a type"
  >>> bool
  'this is not a type'
  

  58toán tử. Nhận thức được hiện tượng đoản mạch là rất quan trọng khi các biểu thức có tác dụng phụ. Trong hai ví dụ cuối cùng, việc đánh giá ngắn mạch ngăn cản tác dụng phụ khi in xảy ra.

Một ví dụ trong đó hành vi này có thể quan trọng là trong mã có thể tạo ra các ngoại lệ:

Hàm 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

>>>

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

Trong hai trường hợp cuối cùng, không có gì được in. Hàm không được gọi vì việc gọi nó không cần thiết để xác định giá trị của 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

Một ví dụ trong đó hành vi này có thể quan trọng là trong mã có thể tạo ra các ngoại lệ:

Hàm 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

Ngược lại, 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> def inverse_and_true(n):
...     1 // n
...     return True
...
>>> inverse_and_true(5)
True
>>> inverse_and_true(0)
Traceback (most recent call last):
  File "", line 1, in 
  File "", line 2, in inverse_and_true
ZeroDivisionError: integer division or modulo by zero
>>> False and inverse_and_true(0)
False

Có mười sáu toán tử Boolean hai đầu vào có thể có. Ngoại trừ 

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

Toán tử so sánh

Một số toán tử của Python kiểm tra xem liệu mối quan hệ có giữ giữa hai đối tượng hay không. Vì mối quan hệ giữ hoặc không giữ, các toán tử này, được gọi là toán tử so sánh , luôn trả về các giá trị Boolean.

Các toán tử so sánh là nguồn phổ biến nhất của các giá trị Boolean.

Bình đẳng và Bất bình đẳng

Các toán tử so sánh phổ biến nhất là toán tử bình đẳng ( 

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

Toán tử bình đẳng ( 

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

Toán tử bình đẳng thường được sử dụng để so sánh các số:

>>>

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

Bạn có thể đã sử dụng toán tử bình đẳng trước đây. Chúng là một số toán tử phổ biến nhất trong Python. Đối với tất cả các đối tượng Python dựng sẵn và đối với hầu hết các lớp của bên thứ ba, chúng trả về giá trị Boolean : 

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Lưu ý: Ngôn ngữ Python không thực thi điều đó 

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

Chỉ đứng sau toán tử bình đẳng phổ biến là toán tử bất bình đẳng ( 

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

Dưới đây là hai ví dụ về toán tử bất đẳng thức Python đang được sử dụng:

>>>

>>> bool

>>> bool = "this is not a type"
>>> bool
'this is not a type'

Bạn có thể đã sử dụng toán tử bình đẳng trước đây. Chúng là một số toán tử phổ biến nhất trong Python. Đối với tất cả các đối tượng Python dựng sẵn và đối với hầu hết các lớp của bên thứ ba, chúng trả về giá trị Boolean : 

>>> lines="""\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """.splitlines()
>>> sum("the" in line.lower() for line in lines) / len(lines)
0.5

>>> lines = """\
... He took his vorpal sword in hand;
...       Long time the manxome foe he sought—
... So rested he by the Tumtum tree
...       And stood awhile in thought.
... """
>>> line_list = lines.splitlines()
>>> "the" in line_list[0]
False
>>> "the" in line_list[1]
True
>>> 0 + False + True # Equivalent to 0 + 0 + 1
1
>>> ["the" in line for line in line_list]
[False, True, True, False]
>>> False + True + True + False
2
>>> len(line_list)
4
>>> 2/4
0.5

Lưu ý: Ngôn ngữ Python không thực thi điều đó 

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True

>>> a_true_alias = True
>>> a_true_alias
True
>>> True = 5
  File "", line 1
SyntaxError: cannot assign to True