len() Built-in Function

Python - len()

Python len() built-in function returns an integer representing the number of items in the given iterable.

In this tutorial, you will learn the syntax of len() function, and then its usage with the help of example programs.

Syntax of len()

The syntax of len() function is

len(object)

where

Parameter	Description
object	An object of type string, bytes, list, range, dictionary, set, or frozen set.

The len() function returns an integer value.

Examples

1. Length of a string

In this example, we will pass a Python String to len() function. len(str) function returns the length of this string.

Python Program

string = 'hello world!'
n = len(string)
print(n)

Output

12

2. Length of bytes object

In this example, we will pass a bytes object to len() function. len(bytes) function returns the number of bytes in the given bytes object.

Python Program

bytes1 = b'\x00\x10'
n = len(bytes1)
print(n)

Output

2

3. Length of a list

In this example, we will pass a list to len() function. len(list) function returns the number of elements present in the list.

Python Program

myList = [25, 74, 'hello']
n = len(myList)
print(n)

Output

3

4. Length of a range

In this example, we will pass a range object to len() function. len(range) function returns the number of sequence of numbers in the range.

Python Program

myRange = range(0, 8)
n = len(myRange)
print(n)

Output

8

5. Length of a dictionary

In this example, we will pass a dictionary to len() function. len(dict) function returns the number of key:value pairs in this dictionary.

Python Program

myDict = {'a':12, 'b':45, 'c':98}
n = len(myDict)
print(n)

Output

3

6. Length of a set

In this example, we will pass a set to len() function. len() function returns the number of elements in this set.

Python Program

mySet = {24, 85, 73, 66}
n = len(mySet)
print(n)

Output

4

7. Length of a frozenset

In this example, we will pass a string to len() function. len(frozenset) function returns the number of elements present in the frozen set.

Python Program

vowels = frozenset(('a', 'e', 'i', 'o', 'u'))
n = len(vowels)
print(n)

Output

2

Summary

In this tutorial of Python Examples, we learned how to use len() function to find the number of items in a given collection or sequence.