Python 3 - String index() Method

Description

The index() method determines if the string str occurs in string or in a substring of string, if the starting index beg and ending index end are given. This method is same as find(), but raises an exception if sub is not found.

Syntax

Following is the syntax for index() method −

str.index(str, beg = 0 end = len(string))

Parameters

• str − This specifies the string to be searched.

• beg − This is the starting index, by default its 0.

• end − This is the ending index, by default its equal to the length of the string.

Return Value

Index if found otherwise raises an exception if str is not found.

Example

#!/usr/bin/python3

str1 = "this is string example....wow!!!"
str2 = "exam";

print (str1.index(str2))
print (str1.index(str2, 10))
print (str1.index(str2, 40))

Result

When we run above program, it produces the following result −

15
15
Traceback (most recent call last):
   File "test.py", line 7, in <module>
      print (str1.index(str2, 40))
ValueError: substring not found
shell returned 1