So I have a number like 7.50x, which I want to convert to 7.5x. I thought about using regular expressions. I can easily match this expression, for example by using re.search('[0-9].[0-9]0x', string). However, I'm confused how to replace every such number using the re.sub method. For example what should be there as the second argument?
re.sub('[0-9].[0-9]0x', ?, string)
re.sub(r'([0-9]\.[0-9])0x', r'\1x', num)
Test
>>> import re
>>> num="7.50x"
>>> re.sub(r'([0-9]\.[0-9])0x', r'\1x', num)
'7.5x'
r'\1x' here \1 is the value saved from the first capturing group, ([0-9]\.[0-9])
eg for input 7.50x the capturing group matches 7.5 which saved in \1
0+(?![1-9])(?=[^.]*$)
Try this.See demo.
http://regex101.com/r/hQ9xT1/14
x=7.50x
re.sub(r"0+(?![1-9])(?=[^.]*$)","",x)
Using positive lookahead and lookbehind assertion.
>>> import re
>>> num="7.50x"
>>> re.sub(r'(?<=\d\.\d)0(?=x)', r'', num)
'7.5x'
(?<=\d\.\d), the number which precedes the digit 0 would be in this digit dot digit format.And the character following the match (0) must be x
\. Matches a literal dot.