I try to use the flag re.MULTILINE .
I read these posts : Bug in Python Regex? (re.sub with re.MULTILINE) , Python re.sub MULTILINE caret match but it doesn't work. The code :
import re
if __name__ == '__main__':
txt = "\n\
<?php\n\
/* Multi-line\n\
comment */\n\
$var = 1;\n"
new_txt = re.sub(r'\/\*[.\n]*?\*\/', '', txt, flags=re.MULTILINE)
print("\n=========== TXT ============")
print(txt)
print("\n=========== NEW TXT ============")
print(new_txt)
The code output :
=========== TXT ============
<?php
/* Multi-line
comment */
$var = 1;
=========== NEW TXT ============
<?php
/* Multi-line
comment */
$var = 1;
But new_txt should not contains Multi-line comment . I want to get the txt without the Multi-line comment. Do you have any idea ?
You need to replace re.MULTILINE
with re.DOTALL
/ re.S
and move out period outside the character class as inside it, the dot matches a literal .
.
Note that re.MULTILINE
only redefines the behavior of ^
and $
that are forced to match at the start/end of a line rather than the whole string. The re.DOTALL
flag redefines the behavior of .
inside the pattern outside the character class only . It starts matching a newline symbol, too.
So, the regex you could use for the current example: /\\*.*?\\*/
. It matches a literal /*
with /\\*
, then .*?
matches as few any symbols as possible up to and including */
(matched with \\*/
).
See the code demo:
txt = """\n\
<?php\n\
/* Multi-line\n\
comment */\n\
$var = 1;\n"""
new_txt = re.sub(r'/\*.*?\*/', '', txt, flags=re.S)
print("\n=========== TXT ============")
print(txt)
print("\n=========== NEW TXT ============")
print(new_txt)
See IDEONE demo
However, it is not the best solution, as in most cases multiline comments are very long. The best is an unrolling-the-loop technique. The regex above can be "unrolled" like this:
/\*[^*]*(?:\*(?!/)[^*]*)*\*/
See the regex demo
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