castiel castiel - 1 month ago 6
Python Question

python regular expression with utf8 issue

I got a file which includes many lines of plain utf-8 text. Such as below, by the by, it's Chinese.

PROCESS:类型:关爱积分[NOTIFY] 交易号:2012022900000109 订单号:W12022910079166 交易金额:0.01元 交易状态:true 2012-2-29 10:13:08


The file itself was saved in utf-8 format. file name is xx.txt

here is my python code, env is python2.7

#coding: utf-8
import re
pattern = re.compile(r'交易金额:(\d+)元')
for line in open('xx.txt'):
match = pattern.match(line.decode('utf-8'))
if match:
print match.group()


The problematic thing here is I got no results.

I wanna get the decimal string from
交易金额:0.01元
, in here, which is
0.01
.

Why doesn't this code work? Can anyone explain it to me, I got no clue whatsoever.

uhz uhz
Answer

There are several issues with your code. First you should use re.compile(ur'<unicode string>'). Also it is nice to add re.UNICODE flag (not sure if really needed here though). Next one is that still you will not receive a match since \d+ doesn't handle decimals just a series of numbers, you should use \d+\.?\d+ instead (you want number, probably a dot and a number). Example code:

#coding: utf-8

text = u"PROCESS:类型:关爱积分[NOTIFY]   交易号:2012022900000109   订单号:W12022910079166    交易金额:0.01元    交易状态:true 2012-2-29 10:13:08"
import re
pattern = re.compile(ur'交易金额:(\d+\.?\d+)元', re.UNICODE)

print pattern.search(text).group(1)