in reply to Re: regexp - replace spaces in quoted string
in thread regexp - replace spaces in quoted string

YAPE::Regex::Explain will help you:

The regular expression:

(?-imsx:s/(".*?")/($x=$1)=~y: :_:, $x/ge)

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  s/                       's/'
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    "                        '"'
----------------------------------------------------------------------
    .*?                      any character except \n (0 or more times
                             (matching the least amount possible))
----------------------------------------------------------------------
    "                        '"'
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
  /                        '/'
----------------------------------------------------------------------
  (                        group and capture to \2:
----------------------------------------------------------------------
    $                        before an optional \n, and the end of
                             the string
----------------------------------------------------------------------
    x=                       'x='
----------------------------------------------------------------------
    $                        before an optional \n, and the end of
                             the string
----------------------------------------------------------------------
    1                        '1'
----------------------------------------------------------------------
  )                        end of \2
----------------------------------------------------------------------
  =~y: :_:,                '=~y: :_:, '
----------------------------------------------------------------------
  $                        before an optional \n, and the end of the
                           string
----------------------------------------------------------------------
  x/ge                     'x/ge'
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

[download]

HTH,


Update: See below for corrections. (Thanks, japhy!)

planetscape

Replies are listed 'Best First'.
Re^3: regexp - replace spaces in quoted string
by uksza (Canon) on Sep 06, 2005 at 11:11 UTC 
    s/(".*?")/($x=$1)=~y: :_:, $x/ge)

[CUT]

  =~y: :_:,                '=~y: :_:, '
----------------------------------------------------------------------
  $                        before an optional \n, and the end of the
                           string
----------------------------------------------------------------------
  x/ge                     'x/ge'

    [download]
    Hm... Is it good explanation??
    I'll try in my poor english: 
    s/(".*?")/($x=$1)=~y: :_:, $x/ge)
^^^^^^^^^1
          ^^^^^^^2
                  ^^^^^^^3
                          ^^4
                             ^^^5

    [download]
    1) take ALL between " and "
    2) So you have ALL in $1. $1 is read only, so copy $1 to $x. And now, for one moment forget about all and work only on $x (this is thanx /e which "wraps an eval{...} around the replacement string and the evaluated result is substituted for the matched substring".
    3)in $x replace all ' ' to '_'
    4)put replaced $x into first s/from/to/
    5)g - works globaly; e - eval the replacment string

    greets
    Uksza
[reply]
[d/l]
[select]

      While the explanation provided by YAPE::Regex::Explain will probably be inferior to that which a human well-versed in regexps could produce, the advantage in using the module is that an explanation can be produced without having access to the well-versed human. It is available to anyone with access to CPAN, and therefore can be quite useful to the learner. :-)

      planetscape
[reply]
        Um, you mis-used my module. Only the LEFT-HAND side of a s/// is a regex; therefore, only the left-hand side should be sent through YAPE::R::E.
        Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
        How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart
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