Python String rindex() method returns the highest index of the substring inside the string if the substring is found. Otherwise, it raises ValueError.
Python String index() Method Syntax
Syntax: str.rindex(sub, start, end)
Parameters:
- sub : It’s the substring which needs to be searched in the given string.
- start : Starting position where sub is needs to be checked within the string.
- end : Ending position where suffix is needs to be checked within the string.
Return: Returns the highest index of the substring inside the string if substring is found. Otherwise it raises an exception.
Python String index() Method Example
text = 'geeks for geeks'
result = text.rindex( 'geeks' )
print ( "Substring 'geeks':" , result)
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Output:
Substring 'geeks': 10
Note: If start and end indexes are not provided then by default Python String rindex() Method takes 0 and length-1 as starting and ending indexes where ending indexes is not included in our search.
Example 1: Python String rindex() Method with start or end index
If we provide the start and end value to check inside a string, Python String rindex() will search only inside that range.
string = "ring ring"
# checks for the substring in the range 0-4 of the string print (string.rindex( "ring" , 0 , 4 ))
# same as using 0 & 4 as start, end value print (string.rindex( "ring" , 0 , - 5 ))
string = "101001010"
# since there are no '101' substring after string[0:3] # thus it will take the last occurrence of '101' print (string.rindex( '101' , 2 ))
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Output:
0 0 5
Example 2: Python String rindex() Method without start and end index
string = "ring ring"
# search for the substring, # from right in the whole string print (string.rindex( "ring" ))
string = "geeks"
# this will return the right-most 'e' print (string.rindex( 'e' ))
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Output:
5 2
Errors and Exceptions:
ValueError: This error is raised when the argument string is not found in the target string.
# Python code to demonstrate error by rindex() text = 'geeks for geeks'
result = text.rindex( 'pawan' )
print ( "Substring 'pawan':" , result)
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Exception:
Traceback (most recent call last): File "/home/dadc555d90806cae90a29998ea5d6266.py", line 6, in result = text.rindex('pawan') ValueError: substring not found