Difference Between find() and index() in Python (original) (raw)

Last Updated : 21 Nov, 2024

Both methods are used to locate the position of a substring within a string but the major difference between **find() and **index()methods in Python is how they handle cases when the substring is not found. The find() method returns **-1 in such cases, while **index() method raises a **ValueError.

Example of find()

Python `

s = "hello world"

Finds the position of the substring "world"

print(s.find("world"))

Returns -1 when substring is not found

print(s.find("python"))

Finds the position of "o" starting from index 5

print(s.find("o", 5))

**Explanation:

s.find(“world”) returns 6 because the substring “world**” starts at index **6.
s.find(“python”) returns -1 as substring “python**” is not present in string.
**s.find(“o”, 5) starts the search from index **5 and finds the first occurrence of “o” at index **7.

Example of index()

Python `

s = "hello world"

Finds position of the substring "world"

print(s.index("world"))

Raises a ValueError when substring is not found

print(s.index("python"))

Finds position of "o" starting from index 5

print(s.index("o", 5))

ERROR! Traceback (most recent call last): File "<main.py>", line 7, in ValueError: substring not found