s="Python programming"p=s.index("prog")print(p)

7

Explanation: index() method searches for the substring "prog" within "Python programming" and returns starting index7.

Syntax of index()

s.index(substring, start=0, end=len(s))

Parameters:

• substring:The substring to locate within the strings.
• start (optional):The starting index for the search. Defaults to0 if not provided.
• end (optional): The ending index for the search. If not provided, it defaults to the length of the string.

Return Type:

• Returns the lowest index of the substring if found in the given string.
• Raises aValueError if the substring is not found in the specified range.

Example of index() Method

Let's understand the use of index() with the help of some examples.

Example 1: Using index() with only substring argument

This code demonstrates how to find the index of a substring within a string using the index() method.

s="Python programming is powerful"p=s.index("programming")print(p)

7

Explanation:

• Here, we only provide the substring argument "programming".
• index() searches from the start of the string and finds "programming" at index 7, which it returns.

Example 2: Using index() with substring, start and end arguments

This code demonstrates how to find the index of a substring within a specific range of a string using the index() method with optional start and end parameters.

s="Python programming is fun"p=s.index("is",10,25)print(p)

19

Explanation:

• We specify start=10andend=25, soindex() searches between these positions.
• It finds "is" at index18 within this range and returns18.