The rfind() 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 return -1. We can also specify the starting and ending positions for the search.
str.rfind(sub[, start[, end]] ) #where start & end are integer values
The rfind() function takes three parameters. This method is similar to the rindex() method the difference is that, if the substring is not found in the rindex() method it will raise a ValueError exception,
| 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 rfind() method always performs a case-sensitive search.
| Input | Return Value |
|---|---|
| If substring | Integer(highest index) |
| If no substring | -1 |
string = "Hii, How are you."
# substring exist
val = string.rfind("o")
print("Substring1 index:", val)
# substring not exist
value = string.rfind("s")
print("Substring2 index:", value)
Output:
Substring1 index: 14 Substring2 index: -1
string = "Python programming language"
# calling function
string2 = string.rfind("m",5) # Only starting index is passed
print("Substring index:", string2)
string2 = string.rfind("o",1,7) # Start and End both indexes are passed
print("Substring index:", string2)
Output:
Substring index: 14 Substring index: 4
