List Methods

index()

Return the zero-based index of the first occurrence of a value.

list.index(value, start=0, stop=len(list))

list.index() searches for value and returns the zero-based index of the first match.

Optional start and stop arguments limit the search to a slice of the list. Raises ValueError if not found.

Parameters

Name	Description
value	The value to locate.
start	Optional start index for the search slice (defaults to 0).
stop	Optional stop index for the search slice (defaults to length of list).

The integer index of the first matching item.

Run it and change it

letters = ["p", "y", "t", "h", "o", "n"]
pos = letters.index("t")
print(f"'t' is at index: {pos}")

Handling ValueErrors: If the element is not found, Python raises ValueError. Check with if item in my_list: or wrap in a try...except ValueError block.