Python Built-in Methods – Python len() Function

Python len() Function

Returns the number of items of an object


The len() function returns the number of items of an object.

The object may be a sequence (such as a string, tuple, list, or range) or a collection (such as a dictionary, set, or frozen set).



Parameter Condition Description
object Required A sequence or a collection.

len() on Sequences

# number of characters in a string
S = 'Python'
x = len(S)
# Prints 6
# number of items in a list
L = ['red', 'green', 'blue']
x = len(L)
# Prints 3
# number of items in a tuple
T = ('red', 'green', 'blue')
x = len(T)
# Prints 3

len() on Collections

# number of key:value pairs in a dictionary
D = {'name': 'Bob', 'age': 25}
x = len(D)
# Prints 2
# number of items in a set
S = {'red', 'green', 'blue'}
x = len(S)
# Prints 3


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