Python’s built-in list() function creates and returns a new list object. When used without an argument, it returns an empty list. When used with the optional iterable argument, it initializes the new list with the elements in the iterable.
Read more about lists in our full tutorial about Python Lists.
Usage
Learn by example! Here are some examples of how to use the list() built-in function:
You can create an empty list by skipping the argument:
>>> list() []
If you pass an iterable—such as another list, a tuple, a set, or a dictionary—you obtain a new list object with list elements obtained from the iterable:
>>> list([1, 2, 3]) [1, 2, 3]
Note that it really creates a new list object that is different from the one passed as an argument:
>>> x = [1, 2, 3] >>> y = list(x) >>> x is y False >>> x == y True
The new list y has the same elements as the original list x. But it’s still a different object as you can see from the check x is y that returns False.
Video list()
Syntax list()
You can use the list() method with or without the optional iterable argument.
Syntax: There are two ways of using the constructor:
list() -> new empty list
list(iterable) -> new list initialized with elements in iterableInteractive Shell Exercise: Understanding list()
Consider the following interactive code:
Exercise: Guess the output before running the code.
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Summary
Python’s built-in list() function creates and returns a new list object.
- When used without an argument, it returns an empty list.
- When used with the optional
iterableargument, it initializes the new list with the elements in the iterable.
>>> list() [] >>> list([1, 2, 3]) [1, 2, 3]
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