String
also have an index
method but also more advanced options and the additional str.find
. For both of these there is a complementary reversed method.
astring = 'Hello on StackOverflow'
astring.index('o') # 4
astring.rindex('o') # 20
astring.find('o') # 4
astring.rfind('o') # 20
The difference between index
/rindex
and find
/rfind
is what happens if the substring is not found in the string:
astring.index('q') # ValueError: substring not found
astring.find('q') # -1
All of these methods allow a start and end index:
astring.index('o', 5) # 6
astring.index('o', 6) # 6 - start is inclusive
astring.index('o', 5, 7) # 6
astring.index('o', 5, 6) # - end is not inclusive
ValueError: substring not found
astring.rindex('o', 20) # 20
astring.rindex('o', 19) # 20 - still from left to right
astring.rindex('o', 4, 7) # 6