What is list.index() in Python?
Among the many list methods in Python is the list.index() method. The list.index() method is used to check for the existence of an item in a list.
Syntax
list.index(element)
Parameters
element: This is a required value of the element of the list of which its index is to be searched for.
Example 1
Let’s find the index of the element of a list of even numbers up to ten.
even_numbers = [2, 4, 6, 8, 10]# to find the index of 2 in the listindex = even_numbers.index(2)print(f'the index of 2 in the list is {index}')# to find the index of 10 in the listindex = even_numbers.index(10)print(f'the index of 10 jn the list is {index}')
Explanation
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Line 1: We create a list of even numbers up to ten.
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Line 4: We create a variable called
indexto return the index value of the number2present in the list usingeven_numbers.index(2). -
Line 5: We return the output of the index variable.
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Line 8: We did the same thing we did on line 4, but this time we checked for the index of the number 10 in the list.
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Line 9: We returned the output of the index variable.
Example 2
Let’s see if we can find the index of an element not present in a list of the countries provided below.
countries = ['Germany', 'France', 'Canada', 'Tunisia','China']index= countries.index('Angola')print(index)
The code above returned a ValueError. This is simply because Angola is not present in the list provided.
