The rindex() function in python helps to return the highest index means the last occurrence of the given substring from the original string. If the substring is not found the function will raise a ValueError exception. We can also specify the starting and ending positions for the search.
str.rindex(sub[, start[, end]] ) #where start & end are integer values
The rindex() function takes three parameters. This method is similar to the rfind() method the difference is that, if the substring is not found in the rfind() method it will return -1 as output.
| Parameter | Description | Required / Optional |
|---|---|---|
| sub | The string to search for | Required |
| start | Where to start the search. Default is 0 | Optional |
| end | Where to end the search. Default is to the end of the string | Optional |
The return value is always an integer. The rindex() method always performs a case-sensitive search.
| Input | Return Value |
|---|---|
| If substring | Integer(highest index) |
| If no substring | ValueError exception |
string = "Hii, How are you."
# substring exist
val = string.rfind("o")
print("Substring1 index:", val)
# substring not exist
print(string.rfind("s"))
Output:
Substring index: 14 Traceback (most recent call last): File "...", line 8, inprint(string.rfind("s")) ValueError: substring not found
string = "Python programming language"
# calling function
string2 = string.rindex("m",5) # Only starting index is passed
print("Substring index:", string2)
string2 = string.rindex("o",1,7) # Start and End both indexes are passed
print("Substring index:", string2)
Output:
Substring index: 14 Substring index: 4
