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Re: regex pattern match
by McA (Priest) on Mar 29, 2013 at 09:35 UTC
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Hi,
take Text::CSV and parse line by line, so you should have all elements A and B and C and D,E,F in one array. Then you access the last element and split it with:
my @lastletters = split /,/, $elements[-1];
if(@lastletters > 1) {
# more than one letter
print "first row\n";
print "additional rows\n";
}
McA | [reply]
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Re: regex pattern match
by hdb (Monsignor) on Mar 29, 2013 at 09:50 UTC
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Unless you have reason to split the first n-1 pieces as well, you only need the last one separated.
Once you have it, you replace the commata with quote, newline, appropriate number of spaces, quote
Voila!
while(<DATA>) {
chomp;
my ($first, $last ) = /(.+",)(.+)/;
print $first;
$first = " " x length( $first );
$last =~ s/,/"\n$first"/g;
print "$last\n";
}
__DATA__
"A","B","C","D"
"A","B","C","D,E,F"
"A","B","C","D"
"A","B","C","D,R,T"
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$first =~ s/./ /g;
I love regular expressions! However, things can get easily out of hand and become unmaintainable. Also, these are quite format dependent. Should there be only one column, it would not work anymore.
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Re: regex pattern match
by vagabonding electron (Curate) on Mar 29, 2013 at 16:27 UTC
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#!/usr/bin/perl
use strict;
use warnings;
use Text::ParseWords;
while ( my $line = <DATA> )
{
chomp $line;
my @fields = quotewords( ',', 0, $line );
my @lastfield;
if ( index( $fields[-1], ',') > -1 )
{
@lastfield = quotewords(',',0,$fields[-1]);
$fields[-1] = shift @lastfield;
}
@fields = map { '"'.$_.'"' } @fields; # if quotes are obligatory
print join( ',', @fields ), "\n";
while ( my $rest = shift @lastfield )
{
$rest = '"'.$rest.'"';
my @temp = (' ') x scalar @fields - 1; # three spaces,
# two of these because of quotes
push @temp, $rest;
print join(' ', @temp ), "\n";
}
}
__DATA__
"A","B","C","D"
"A","B","C","D,E,F"
"A","B","C","D"
"A","B","C","D,R,T"
The output:
"A","B","C","D"
"A","B","C","D"
"E"
"F"
"A","B","C","D"
"A","B","C","D"
"R"
"T"
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Re: regex pattern match
by kcott (Archbishop) on Mar 30, 2013 at 06:34 UTC
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$ cat fred.dat
"A","B","C","D"
"A","B","C","D,E,F"
"A","B","C","D"
"A","B","C","D,R,T"
$ perl -Mstrict -Mwarnings -E '
while (<>) {
my ($start, $end) = /^(.+?)("[^"]+")$/;
my @finals = split /,/ => substr $end, 1, -1;
say $start, q{"}, shift(@finals), q{"};
say q{ } x length($start), q{"}, shift(@finals), q{"} while @final
+s;
}
' fred.dat
"A","B","C","D"
"A","B","C","D"
"E"
"F"
"A","B","C","D"
"A","B","C","D"
"R"
"T"
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Re: regex pattern match
by reaper9187 (Scribe) on Apr 01, 2013 at 17:42 UTC
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Oh .. i'm sorry ,...
The problem was with the regex replacing the directory path within the double quotes.$current_path and $new_path are two variables that i need for substitution.Then i perform a simple regex substitution. However, the double quotes and backslash made it extra hard to perform regex matching ..
. The answer may not look great but it works.!!
$line =~s/\Q$current_path/$new_path\E/ig;
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Re: regex pattern match
by reaper9187 (Scribe) on Mar 29, 2013 at 09:41 UTC
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Hi .. Thank you for the quick reply .. Is it somehow possible to do it without using any module...??
I've reached thus far with the code
$in_file = "test.txt";
$out_file = "testout.txt";
open (IN, "<$in_file") or die "Can't open $in_file: $!\n";
open (OUT, ">$out_file") or die "Can't open $out_file: $!\n";
while ( $line = <IN> ) {
@fields = split /,/, $line;
$line = join ",", $fields[0], @fields[1..5];
print OUT $line;
print OUT "\n";
}
close IN;
close OUT;
#read in output file and print to screen to confirm
open (TEST, "<$out_file") or die "Can't open $out_file: $!\n";
while ( <TEST> ) {
print;
}
close TEST;
There's only one problem bugging me .. How do i exclude the double quoted string from the pattern match in the split statement ..Once i am able to do that , the rest should be easy.. else it jus increases the amount of processing i need to do... | [reply]
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#strip LF from line
chomp $line;
# delete the very first and last " from line
for ($line) {
s/^\s*"//;
s/"\s*$//;
}
# now split
@fields = split /"\s*,\s*"/, $line;
# now you should have the pieces I mentioned above
McA | [reply]
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Re: regex pattern match
by reaper9187 (Scribe) on Apr 01, 2013 at 14:16 UTC
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Ok .. So here's the breakup.
I have a text file filled with entries like :
"ABC","DEF","B","C:\Users\Dave\Documents";
The user inputs the following arguments:
1. The part of text to be replaced
2. The new text(to replace the substituted text)
So for eg: the User i/p for the text to be replaced(option1) is : C:\Users\Dave
and the I/p for option2 is : E:\Dave
the final output should be:
"ABC","DEF","B","E:\Dave\Documents";
Please help ..1!!
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Re: regex pattern match
by reaper9187 (Scribe) on Apr 01, 2013 at 10:08 UTC
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A quick addition to the problem .. I have a separate part of text that i need to replace .. for eg:
I/p(read from a file) is of the form:
"ABC","DEF","This is a test","Hello";
and the o/p needs to look something like :
"ABC","DEF","This is a substitution","Hello";
In short i need to replace pattern within quotes in a line .. I need help with the pattern match .. please help ..!!!
Update:
Could some one please help me debug this code..??
#!/usr/bin/perl -w
my $variable;
my @fields;
my $line =0 ;
use vars qw($current_path $filename);
print "Enter the desired path: ";
my $path = <STDIN>;
chomp( $path );
my $in_file = "test.txt";
my $out_file = "testout.txt";
open (DATA, "<$in_file") or die "Can't open $in_file: $!\n";
open (OUT, ">$out_file") or die "Can't open $out_file: $!\n";
while ( <DATA> ) {
chomp;
my ($first, $last ) = /(.+",)(.+)/;
$last =~ s//"\n$first"/g;
my @parameters = split /"\s*,\s*"/, $first;
$parameters[1] =~ tr/"//d;
my $path = "$path\\";
my $new_path = $path.$parameters[1];
@array = split(/,/,$last);
foreach $entry(@array)
{
$entry =~ tr/"//d;
$entry =~ s|(.+)\\|$1::|;
($current_path,$filename) = split/::/,$entry;
$last =~s/$current_path/$new_path/ig; #rename the last entry which con
+tains a path to folder name with the new path
print "$last\n";
}
print "\n";
}
close DATA;
close OUT;
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my ($first, $last ) = /(.+",)(.+)/;
$last =~ s//"\n$first"/g;
I second hdb's reply in general.
Let me add that the
$last =~ s//"\n$first"/g;
statement from the posted code quoted above is very unlikely to do what you want: it will match the // null regex pattern globally and do a substitution against what is matched. If there has been a previous successful regex match (e.g., the match in the preceding line), the // regex matches using the previously matched regex. (If there has been no previous successful regex match, the // regex matches anything!) As it stands, this substitution seems to be a no-op. If it is part of some carefully thought out strategy, I advise you to abandon it immediately: it has 'maintenance nightmare' written all over it! (In the code example below, \x22 stands in for an unbalanced " (double-quote) character.)
>perl -wMstrict -le
"$_ = qq{\"ABC\",\"DEF\",\"This is a test\",\"Hello\"};
;;
my ($first, $last ) = /(.+\x22,)(.+)/;
print qq{'$last'};
;;
$last =~ s//\"\n$first\"/g;
print qq{'$last'};
"
'"Hello"'
'"Hello"'
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Re: regex pattern match
by reaper9187 (Scribe) on Apr 01, 2013 at 14:37 UTC
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ok .. so i've figured out the solution as soon as i posted this .. Thanks everyone for the help.. :) | [reply] |
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