Python List - index() Method

The Python index() method returns the index number of first occurrence of the specified element in the list. It returns the zero-based index.

The method raises a ValueError, if the specified element is not found.

Syntax

list.index(elem, start, end)

Parameters

`elem`	`Required.` Specify the value of the element which need to be searched in the list.
`start`	`Optional.` Specify the starting point of the search in the list.
`end`	`Optional.` Specify the end point of the search in the list.

Return Value

Returns the index number of first occurrence of the specified element in the list.

Example:

In the example below, index() method is used to find out index number of first occurrence of an element called 'MAR' in the list called MyList

MyList = ['JAN', 'FEB', 'MAR', 'APR', 'MAR']

#first occurrence of 'MAR' in the whole list
x = MyList.index('MAR') 
print("The index of 'MAR' is:", x)

The output of the above code will be:

The index of 'MAR' is: 2

Example:

In this example, index() method is used with optional arguments to find out the index number of first occurrence of 10 in the specified list.

MyList = [10, 20, 30, 40, 50, 10, 70, 80]

#first occurrence of 10 in the whole list
x = MyList.index(10) 
print("The index of 10 is:", x)

#first occurrence of 10 in the specified
#section of the list
y = MyList.index(10, 1, 8) 
print("The index of 10 in index range [1,8) is:", y)

The output of the above code will be:

The index of 10 is: 0
The index of 10 in index range [1,8) is: 5

❮ Python List Methods