What is the difference between iterator and list in python?
Iterable is an object, that one can iterate over. It generates an Iterator when passed to iter() method. An iterator is an object, which is used to iterate over an iterable object using the __next__() method. Iterators have the __next__() method, which returns the next item of the object. Note that every iterator is also an iterable, but not every iterable is an iterator. For example, a list is iterable but a list is not an iterator. An iterator can be created from an iterable by using the function iter(). To make this possible, the class of an object needs either a method __iter__, which returns an iterator, or a __getitem__ method with sequential indexes starting with 0. Show Code #1 Python3Output : Traceback (most recent call last): File "/home/1c9622166e9c268c0d67cd9ba2177142.py", line 2, in We know that str is iterable but it is not an iterator. where if we run this in for loop to print string then it is possible because when for loop executes it converts into an iterator to execute the code. Python3Here iter( ) is converting s which is a string (iterable) into an iterator and prints G for the first time we can call multiple times to iterate over strings. When a for loop is executed, for statement calls iter() on the object, which it is supposed to loop over. If this call is successful, the iter call will return an iterator object that defines the method __next__(), which accesses elements of the object one at a time. The __next__() method will raise a StopIteration exception if there are no further elements available. The for loop will terminate as soon as it catches a StopIteration exception. Let’s call the __next__() method using the next() built-in function. Code #2: Function ‘iterable’ will return True if the object ‘obj’ is an iterable and False otherwise. Python3
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Code #3: Check object is iterable or not Output: 34 is iterable : False [4, 5] is iterable : True (4, 5) is iterable : True {'a': 4} is iterable : True dfsdf is iterable : True 4.5 is iterable : False Summary: in this tutorial, you’ll learn about Python iterator and iterable and their differences. IteratorsAn iterator is an object that implements the iterator protocol. In other words, an iterator is an object that implements the following methods:
Once you complete iterating a collection using an iterator, the iterator becomes exhausted. It means that you cannot use the iterator object anymore. IterablesAn iterable is an object that you can iterate over. An object is iterable when it implements the Examining the built-in list and list iteratorIn Python, a list is an ordered collection of items. It’s also an iterable because a list object has the
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Error:
This is because the list iterator has been exhausted. To iterate the list again, you need to create a new iterator. This illustrates the separating the list from its iterator. The list is created once while the iterator is created every time you need to iterate over the list. The following defines the
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Separating an iterator from an iterableLet’s separate the color iterator from its iterable like what Python does with the list iterator and list. The following defines the
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Summary
Did you find this tutorial helpful ? What is the difference between iterator and list?Iterator can traverse only in forward direction whereas ListIterator traverses both in forward and backward directions. ListIterator can help to replace an element whereas Iterator cannot. Can traverse elements present in Collection only in the forward direction.
Is Python list an iterator?Lists, tuples, dictionaries, and sets are all iterable objects. They are iterable containers which you can get an iterator from.
What is the difference between an iterator and iterable in Python?An Iterable is basically an object that any user can iterate over. An Iterator is also an object that helps a user in iterating over another object (that is iterable). We can generate an iterator when we pass the object to the iter() method. We use the __next__() method for iterating.
Is list iterable or iterator in Python?For example, a list is iterable but a list is not an iterator. An iterator can be created from an iterable by using the function iter(). To make this possible, the class of an object needs either a method __iter__, which returns an iterator, or a __getitem__ method with sequential indexes starting with 0.
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