Python中的正则表达式，用于匹配CSV文件中的字符串

Question

I am working with regular expressions in Python. I want to match a few lines from a CSV file inserted into a database that starts and ends with an underscore.

I have used regular expressions in my Python script to do the same but it prints the result as 'none'. Here is my code for the same, kindly tell me what mistake I am making:

reg = re.compile(r'^_.*_$',re.I)
imatch = reg.match(unicode(row[4], "utf8"))

Here r'^_.*_$',re.I is my regular expression to match lines starting and ending with _. unicode(row[4], "utf8") specifies the row from the CSV file inserted into a database.

Any help would be appreciated.

Answer 1

import re
lines = [line.strip() for line in open('file.csv')]
for x in lines:
    match=re.search(r'^_.*_$',x)
    if match: print x

we have to strip each line otherwise each line ends with char '\\n' instead of '_' in that case regex won't match the string.

file.csv

_abdlfla_
sldjlfds_
_adlfdls
_132jdlfjflds_

output

_abdlfla_
_132jdlfjflds_

Answer 2

You may use startswith and endswith function instead of re. Any specific reason for using re?

for l in open('test.csv'):
    l=l.strip()
    if l.startswith('_') and l.endswith('_'):
        print(l)