How can I convert string into integer and remove every character from that change. Example:
S = "--r10-" I want to have this: S = 10
This not work:
S = "--10-"
int(S)
-
I'm not sure whether you know how you strings look like but you can always use regular expressions to get the relevant information out. \d gives you numbersDaniel Wehner– Daniel Wehner2011-11-15 21:32:01 +00:00Commented Nov 15, 2011 at 21:32
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6 Answers
You can use filter(str.isdigit, s) to keep only those characters of s that are digits:
>>> s = "--10-"
>>> int(filter(str.isdigit, s))
10
Note that this might lead to unexpected results for strings that contain multiple numbers
>>> int(filter(str.isdigit, "12 abc 34"))
1234
or negative numbers
>>> int(filter(str.isdigit, "-10"))
10
Edit: To make this work for unicode objects instead of str objects, use
int(filter(unicode.isdigit, u"--10-"))
2 Comments
DRdr
I have this message in my code: 'descriptor 'isdigit' requres a 'str' object but recived a 'unicode' :( any suggestion?
Andrew Clark
You could also use
operator.methodcaller("isdigit") so it will work with both str and unicode.remove all non digits first like that:
int(''.join(c for c in "abc123def456" if c.isdigit()))
Comments
You could just strip off - and r:
int("--r10-".strip('-r'))
Comments
use regex replace with /w to replace non word characters with "" empty string. then cast it
Comments
I prefer Sven Marnach's answer using filter and isdigit, but if you want you can use regular expressions:
>>> import re
>>> pat = re.compile(r'\d+') # '\d' means digit, '+' means one or more
>>> int(pat.search('--r10-').group(0))
10
If there are multiple integers in the string, it pulls the first one:
>>> int(pat.search('12 abc 34').group(0))
12
If you need to deal with negative numbers use this regex:
>>> pat = re.compile(r'\-{0,1}\d+') # '\-{0,1}' means zero or one dashes
>>> int(pat.search('negative: -8').group(0))
-8
answered Nov 15, 2011 at 21:59
Steven Rumbalski
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Comments
This is simple and does not require you to import any packages.
def _atoi(self, string):
i = 0
for c in string:
i += ord(c)
return i
