Python String rindex() Method

Searches the string for a given substring, starting from the right

Usage

The rindex() method searches for the last occurrence of the specified substring sub and returns its index. If specified substring is not found, it raises ValueError exception.

The optional arguments start and end are used to limit the search to a particular portion of the string.

Syntax

string.rindex(sub,start,end)

Python string rindex() method parameters
Parameter	Condition	Description
sub	Required	Any string you want to search for
start	Optional	An index specifying where to start the search. Default is 0.
end	Optional	An index specifying where to stop the search. Default is the end of the string.

Basic Examples

# Find the index of last occurrence of the substring 'Big'
S = 'Big, Bigger, Biggest'
x = S.rindex('Big')
print(x)
# Prints 13

rindex() method raises ValueError exception, if specified substring is not found in the string.

S = 'Big, Bigger, Biggest'
x = S.rindex('Small')
print(x)
# Triggers ValueError: substring not found

Limit the rindex() Search

If you want to search the string from the middle, specify the start and end parameter.

# Search the string from position 2 to 10
S = 'Big, Bigger, Biggest'
x = S.rindex('Big',2,10)
print(x)
# Prints 5

rindex() vs rfind()

The rindex() method is identical to the rfind() method. The only difference is that the rfind() method returns -1 (instead of raising a ValueError), if the substring is not found.

# rfind()
S = 'Big, Bigger, Biggest'
x = S.rfind('Small')
print(x)
# Prints -1

# rindex()
S = 'Big, Bigger, Biggest'
x = S.rindex('Small')
print(x)
# Triggers ValueError: substring not found