index() : case sensitive search of sub string inside main string with optional start and end position

my_str.index(search_string,start,end))

search_string : String to be checked inside the main string.
start: Optional , search to start from this position
end : Optional , search to end from this position.

Check if the search string is within our main string, if found then the position of matching string is returned. If not found then this method raise an exception.

my_str="Welcome to plus2net.com"
print(my_str.index('co'))      # Output is 3
print(my_str.index('co',4))    # Output is 20 
print(my_str.index('co',4,18)) # ValueError: substring not found

Case sensitive

index() is a case sensitive search

my_str="Welcome to plus2net.com"
print(my_str.index('CO'))      # ValueError: substring not found

index() and find()

We can use find() method also to search the position but find() method returns -1 if not found but index() method raise an exception if not found.

All String methods

find tuple Python- Tutorials

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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