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.