Python re.sub

1.

　　

re.sub? Signature:re.sub (Pattern, REPL, String, Count=0, flags=0) Docstring:return the string obtained by replacing the L Eftmostnon in string by Thereplacement repl.   or a callable; if  in it is processed.   is a callable, it ' s passed the match object and must returna replacement string to be used.

Parameter description: Pattern string, can be numerically named can also name name (\g<1>==\1) (?). P<name>----------------\g<name>)

Repl replaced string can also be a function string source string

Count substitution number of times

The value of flag is:

Re. I    make the match to case insensitive re. L    do localization recognition (locale-aware) to match re. M    multi-line match, affecting ^ and $re. S    makes. Matches all characters including line breaks RE.U    characters based on the Unicode character set. This flag affects \w, \w, \b, and \bre.x    this flag by giving you a more flexible format so that you can write regular expressions easier to understand

2. Example

　　

def Replace_digit (m):     = u' 0 123456789 '    = int (m.group ())    return  = u'March 27, 1990 '= re.sub (u'\d' , Replace_digit, S, count=4)print#  March 27, 1990

' 2017-01-22 '  = re.sub ('(\d{4})-(\d{2})-(\d{2})', R'\2-\3-\1' , s) Print # 01-22-2017

　　

Python re.sub