freeCodeCamp/guide/english/python/len-function/index.md

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Python Len Function

len() is a built-in function in Python 3. This method returns the length (the number of items) of an object. It takes one argument x.

Arguments

It takes one argument, x. This argument may be a sequence (such as a string, bytes, tuple, list, or range) or a collection (such as a dictionary, set, or frozen set).

Return Value

This function returns the number of elements in the argument which is passed to the len() function.

Code Sample

    >>> list1 = [123, 'xyz', 'zara'] # list
    >>> print(len(list1)) # prints 3 as there are 3 elements in the list1
    3

    >>> str1 = 'basketball' # string
    >>> print(len(str1)) # prints 10 as the str1 is made of 10 characters
    10

    >>> tuple1 = (2, 3, 4, 5) # tuple 
    >>> print(len(tuple1)) # prints 4 as there are 4 elements in the tuple1
    4

    >>> dict1 = {'name': 'John', 'age': 4, 'score': 45} # dictionary
    >>> print(len(dict1)) # prints 3 as there are 3 key and value pairs in the dict1
    3

    >>> d2=[[1,2,3],[3,4,5],[5,6,7,2]] # 2 dimensional list or a list of lists
    >>> print(len(d2)) #prints 3 because there are 3 different lists in the outer list.
    3

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