❮ String Methods
Example
Check if all the characters in the text are alphanumeric:
txt = "Company12"
x = txt.isalnum[]
print[x]
Try it Yourself »
Definition and Usage
The isalnum[]
method returns True if
all the characters are alphanumeric, meaning alphabet letter [a-z] and numbers [0-9].
Example of characters that are not alphanumeric: [space]!#%&? etc.
Syntax
Parameter Values
No parameters.
More Examples
Example
Check if all the characters in the text is alphanumeric:
txt = "Company 12"
x = txt.isalnum[]
print[x]
Try it Yourself »
❮ String Methods
Python string isalnum[] function returns True
if it’s made of alphanumeric characters only. A character is alphanumeric if it’s either an alpha or a number. If the string is empty, then isalnum[] returns False
.
Python string isalnum[] example
s = 'HelloWorld2019'
print[s.isalnum[]]
Output: True
s = 'Hello World 2019'
print[s.isalnum[]]
Output: False
because whitespace is not an alphanumeric character.
s = ''
print[s.isalnum[]]
Output: False
because it’s an empty string.
s='A.B'
print[s.isalnum[]]
s = '10.50'
print[s.isalnum[]]
Output:
False
False
The string contains period [.] which is not an alphanumeric character.
s = 'çåøÉ'
print[s.isalnum[]]
Output: True
because all these are Alpha characters. Alphabetic characters are those characters defined in the Unicode character database as “Letter”, i.e., those with general category
property being one of “Lm”, “Lt”, “Lu”, “Ll”, or “Lo”.
Printing all Alphanumeric characters in Python
We can use unicode
module to check if a character is alphanumeric or not. Here is the program to print all the alphanumeric unicode characters.
import unicodedata
count = 0
for codepoint in range[2 ** 16]:
ch = chr[codepoint]
if ch.isalnum[]:
print[u'{:04x}: {} [{}]'.format[codepoint, ch, unicodedata.name[ch, 'UNNAMED']]]
count = count + 1
print[f'Total Number of Alphanumeric Unicode Characters = {count}']
Output:
...
ffd7: ᅲ [HALFWIDTH HANGUL LETTER YU]
ffda: ᅳ [HALFWIDTH HANGUL LETTER EU]
ffdb: ᅴ [HALFWIDTH HANGUL LETTER YI]
ffdc: ᅵ [HALFWIDTH HANGUL LETTER I]
Total Number of Alphanumeric Unicode Characters = 49567
I have provided only partial output because the number of alphanumeric unicode characters is huge.
You can checkout more Python examples from our GitHub Repository.
Reference: Official Documentation
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Python String isalnum[] method checks whether all the characters in a given string are either alphabet or numeric [alphanumeric] characters.
Python String isalnum[] Method Syntax:
Syntax: string_name.isalnum[]
Parameter: isalnum[] method takes no parameters
Return:
- True: If all the characters are alphanumeric
- False: If one or more characters are not alphanumeric
Python String isalnum[] Method Example:
Python program to demonstrate the use of String isalnum[] method
Python
string
=
"abc123"
print
[string.isalnum[]]
Output:
True
Example 1: More examples on Python String isalnum[] Method
Python3
string
=
"abc 123"
print
[string,
"is alphanumeric?"
, string.isalnum[]]
string
=
"abc_123"
print
[string,
"is alphanumeric?"
, string.isalnum[]]
string
=
"000"
print
[string,
"is alphanumeric?"
, string.isalnum[]]
string
=
"aaaa"
print
[string,
"is alphanumeric?"
, string.isalnum[]]
Output:
abc 123 is alphanumeric? False abc_123 is alphanumeric? False 000 is alphanumeric? True aaaa is alphanumeric? True
Example 2: isalnum[] in if…else Statement
We can also use Python String isalnum[] Method along with if…else statements, to output custom messages
Python3
password
=
"user123456"
if
password.isalnum[]:
print
[
"Password is alphanumeric."
]
else
:
print
[
"Password is not alphanumeric."
]
Output:
Password is alphanumeric.