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in reply to In-place regex substitution

If you want to change the string in place, you can use s///ge: 
use warnings;
use strict;

my $content = '{ "geometry": { "type": "Polygon", "coordinates": [ [ [
+ 19.054804912278406, 47.485785556135411 ], [ 19.057857836771483, 47.4
+87322542030711 ], [ 19.06025597925397, 47.488491565765209 ], [ 19.060
+347248086835, 47.488539642204628 ], [ 19.060463310421543, 47.48457828
+7406251 ], [ 19.054804912278406, 47.485785556135411 ] ] ] } }';

$content =~ s/(\d\d\.\d*)/substr($1,0,9)/ge;
print "$content\n";

__END__

{ "geometry": { "type": "Polygon", "coordinates": [ [ [ 19.054804, 47.
+485785 ], [ 19.057857, 47.487322 ], [ 19.060255, 47.488491 ], [ 19.06
+0347, 47.488539 ], [ 19.060463, 47.484578 ], [ 19.054804, 47.485785 ]
+ ] ] } }

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Re^2: In-place regex substitution
by AnomalousMonk (Archbishop) on Dec 10, 2016 at 00:06 UTC

    Or without explicit capturing or evaluation (or rounding!) (update: and with dynamic control of truncation threshold), but needs Perl version 5.10+ for  \K operator: 

    c:\@Work\Perl\monks>perl -wMstrict -le
"use 5.010;
 ;;
 my $content
   = qq/{ \"geometry\": { \"type\": \"Polygon\", \"coordinates\": [ [ 
+[ 19.05480
4912278406, \n/
   . qq/47.485785556135411 ], [ 19.057857836771483, 47.487322542030711
+ ], [ 19.06025597925397, \n/
   . qq/47.488491565765209 ], [ 19.060347248086835, 47.488539642204628
+ ], [ 19.060463310421543, \n/
   . qq/47.484578287406251 ], [ 19.054804912278406, 47.485785556135411
+ ] ] ] } } \n/
   ;
 print qq{[[$content]]};
 ;;
 my $n = 7;
 $content =~ s{ \d [.] \d{$n} \K \d+ }{}xmsg;
 ;;
 print qq{<<$content>>};
"
[[{ "geometry": { "type": "Polygon", "coordinates": [ [ [ 19.054804912
+278406,
47.485785556135411 ], [ 19.057857836771483, 47.487322542030711 ], [ 19
+.06025597925397,
47.488491565765209 ], [ 19.060347248086835, 47.488539642204628 ], [ 19
+.060463310421543,
47.484578287406251 ], [ 19.054804912278406, 47.485785556135411 ] ] ] }
+ }
]]
<<{ "geometry": { "type": "Polygon", "coordinates": [ [ [ 19.0548049,
47.4857855 ], [ 19.0578578, 47.4873225 ], [ 19.0602559,
47.4884915 ], [ 19.0603472, 47.4885396 ], [ 19.0604633,
47.4845782 ], [ 19.0548049, 47.4857855 ] ] ] } }
>>

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    Give a man a fish:  <%-{-{-{-<

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Re^2: In-place regex substitution
by lmocsi (Novice) on Dec 09, 2016 at 21:45 UTC
    Great, thx! :)
[reply]
      Are you sure that a number can't have more than 9 digits before the point?

      You might prefer sprintf instead of substr in order to just shorten the digits after the point.

      Cheers Rolf
      (addicted to the Perl Programming Language and ☆☆☆☆ :)
      Je suis Charlie!

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