How to Get Index/Position of Item in Python List

John on May 28, 2021

To get the position of an element in a Python list, use the index() function. Pass .index() after the list to evaluate and the value of the element to look for as the first argument.

Let's try this out with an example.

items = ['a','b','c']

pos = items.index('c')

print(pos)

2

Note - The behaviour of index() is to return the position of the first item found only.

If the Value is Not in the List

If the value is not found in the list, index() will throw a ValueError.

items = ['a','b','c']

pos = items.index('d')

print(pos)

ValueError: 'd' is not in list

To avoid this error, use index() inside a Python try except statement like this:

items = ['a','b','c']

try:
   pos = items.index('d')
except:
   pos = False
   
print(pos)

False

Find Position of Item Within an Index Range

The index() function accepts two more arguments. The second is the index to begin searching from and the third is where to stop searching.

In the example below, if the value 'c' is not found between index 0 and 1, False will be returned.

items = ['a','b','c']

try:
   pos = items.index('c', 0, 2)
except:
   pos = False
   
print(pos)

False