74

I am trying to print the last part of a string before a certain character.

I'm not quite sure whether to use the string .split() method or string slicing or maybe something else.

Here is some code that doesn't work but I think shows the logic: 

x = 'http://test.com/lalala-134'
print x['-':0] # beginning at the end of the string, return everything before '-'

Note that the number at the end will vary in size so I can't set an exact count from the end of the string.

Wolf
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user1063287
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2 Answers2

133

You are looking for str.rsplit(), with a limit:

print x.rsplit('-', 1)[0]

.rsplit() searches for the splitting string from the end of input string, and the second argument limits how many times it'll split to just once.

Another option is to use str.rpartition(), which will only ever split just once:

print x.rpartition('-')[0]

For splitting just once, str.rpartition() is the faster method as well; if you need to split more than once you can only use str.rsplit().

Demo:

>>> x = 'http://test.com/lalala-134'
>>> print x.rsplit('-', 1)[0]
http://test.com/lalala
>>> 'something-with-a-lot-of-dashes'.rsplit('-', 1)[0]
'something-with-a-lot-of'

and the same with str.rpartition()

>>> print x.rpartition('-')[0]
http://test.com/lalala
>>> 'something-with-a-lot-of-dashes'.rpartition('-')[0]
'something-with-a-lot-of'
Martijn Pieters
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    thank you very much, i used `print x.rsplit('-',1)[1]` and it worked, thank you. i had also just come across `print x.rpartition('-')[2]` and that seemed to work too! thanks again! – user1063287 Apr 06 '13 at 13:52
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    Right, your wording was a little ambiguous; you asked for * last part of a string **before** a certain character*; you meant after, I guess. :-) – Martijn Pieters Apr 06 '13 at 13:53
  • but my wonderful comments! 'beginning at the end of the string', i see what you mean haha. – user1063287 Apr 06 '13 at 14:08
5

Difference between split and partition is split returns the list without delimiter and will split where ever it gets delimiter in string i.e.

x = 'http://test.com/lalala-134-431'

a,b,c = x.split(-)
print(a)
"http://test.com/lalala"
print(b)
"134"
print(c)
"431"

and partition will divide the string with only first delimiter and will only return 3 values in list

x = 'http://test.com/lalala-134-431'
a,b,c = x.partition('-')
print(a)
"http://test.com/lalala"
print(b)
"-"
print(c)
"134-431"

so as you want last value you can use rpartition it works in same way but it will find delimiter from end of string

x = 'http://test.com/lalala-134-431'
a,b,c = x.rpartition('-')
print(a)
"http://test.com/lalala-134"
print(b)
"-"
print(c)
"431"
dvijparekh
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