if ($search =~ /\W/){ #if search pattern has any special character
$sentence =~ s/\Q$search\E\b/$replace/g; #\Q..\E will consider special characters. \b is for word boundary
}
else {
$sentence =~ s/\b$search\b/$replace/g; #no need \Q..\E if not spl characters
}
}
print $sentence;
the else part is causing a problem as it is replacing +time1 as well as time1. Is there a single regex expression to take care of this situation so that I need not use if else?
my %map = (
"time1" => "...",
"+time1" => "...",
"time11" => "...",
"+time11" => "...",
);
my $pat =
join "|",
map quotemeta,
sort { length($b) <=> length($a) }
keys(%map);
s/($pat)/$map{$1}/g
#!/usr/bin/perl
use Data::Dumper;
$text = 'time1+............time1.............time11.............+time11...............';
print Dumper $text;
$text =~ s/(.*)(time1)([^0-9].*)/$1$3/g;
print Dumper $text;
Output is:
$VAR1 = 'time1+............time1.............time11.............+time11...............';
$VAR1 = 'time1+.........................time11.............+time11...............';
If depends on the expected results.
Alternatively, to replace only time1:
#!/usr/bin/perl
use Data::Dumper;
$text = '............time1............+time1.............time11.............+time11...............';
print Dumper $text;
$text =~ s/(.*)([^\+]time1)([^0-9].*)/$1$3/g;
print Dumper $text;
Outputs:
$VAR1 = '............time1............+time1.............time11.............+time11...............';
$VAR1 = '.......................+time1.............time11.............+time11...............';
I am trying to match a word that starts with a letter and is followed by at .
I use this regex for it
use strict;
use warnings;
use Data::Dumper;
my $str = "fat 123 cat sat on the mat";
my #a = $str =~ /(\s?[a-z]{1,2}(at)\s?)/g;
print Dumper( #a );
the out put I am getting is:
$ perl ~/playground/regex.pl
$VAR1 = 'fat ';
$VAR2 = 'at';
$VAR3 = ' cat ';
$VAR4 = 'at';
$VAR5 = 'sat ';
$VAR6 = 'at';
$VAR7 = ' mat';
$VAR8 = 'at';
why does it match "at" as well when I clearly say match just 1 character before at.
Your optional spaces aren't a good way to delimit words: they are optional
Use the word boundary construct \b for a rough match to the ends of words
use strict;
use warnings;
use Data::Dumper;
my $str = "fat 123 cat sat on the mat";
my #aa = $str =~ /\b[a-z]+at\b/gi;
print Dumper \#aa;
output
$VAR1 = [
'fat',
'cat',
'sat',
'mat'
];
If you want to be more clever and be certain that the word found isn't preceded or followed by a non-space character then you can write this instead
my #aa = $str =~ /(?<!\S)[a-z]+at(?!\S)/gi;
which produces the same result for the data you show
I'm trying to dynamically catch regex matching in Perl. I've known that eval will help me do this but I may be doing something wrong.
Code:
use strict;
use warnings;
my %testHash = (
'(\d+)\/(\d+)\/(\d+)' => '$1$2$3'
);
my $str = '1/12/2016';
foreach my $pattern (keys (%testHash)) {
my $value = $testHash{$pattern};
my $result;
eval {
local $_ = $str;
/$pattern/;
print "\$1 - $1\n";
print "\$2 - $2\n";
print "\$3 - $3\n";
eval { print "$value\n"; }
}
}
Is it also possible to store captured regex patterns in an array?
I believe what you really want is a dynamic version of the following:
say $str =~ s/(\d+)\/(\d+)\/(\d+)/$1$2$3/gr;
String::Substitution provides what we need to achieve that.
use String::Substitution qw( gsub_copy );
for my $pattern (keys(%testHash)) {
my $replacement = $testHash{$pattern};
say gsub_copy($str, $pattern, $replacement);
}
Note that $replacement can also be a callback. This permits far more complicated substitutions. For example, if you wanted to convert 1/12/2016 into 2016-01-12, you could use the following:
'(\d+)/(\d+)/(\d+)' => sub { sprintf "%d-%02d-%02d", #_[3,1,2] },
To answer your actual question:
use String::Substitution qw( interpolate_match_vars last_match_vars );
for my $pattern (keys(%testHash)) {
my $template = $testHash{$pattern};
$str =~ $pattern # Or /$pattern/ if you prefer
or die("No match!\n");
say interpolate_match_vars($template, last_match_vars());
}
I am not completely sure what you want to do here, but I don't think your program does what you think it does.
You are useing eval with a BLOCK of code. That's like a try block. If it dies inside of that eval block, it will catch that error. It will not run your string like it was code. You need a string eval for that.
Instead of explaining that, here's an alternative.
This program uses sprintf and numbers the parameters. The %1$s syntax in the pattern says _take the first argument (1$) and format it as a string (%s). You don't need to localize or assign to $_ to do a match. The =~ operator does that on other variables for you. I also use qr{} to create a quoted regular expression (essentially a variable containing a precompiled pattern) that I can use directly. Because of the {} as delimiter, I don't need to escape the slashes.
use strict;
use warnings;
use feature 'say'; # like print ..., "\n"
my %testHash = (
qr{(\d+)/(\d+)/(\d+)} => '%1$s.%2$s.%3$s',
qr{(\d+)/(\d+)/(\d+) nomatch} => '%1$s.%2$s.%3$s',
qr{(\d+)/(\d+)/(\d\d\d\d)} => '%3$4d-%2$02d-%1$02d',
qr{\d} => '%s', # no capture group
);
my $str = '1/12/2016';
foreach my $pattern ( keys %testHash ) {
my #captures = ( $str =~ $pattern );
say "pattern: $pattern";
if ($#+ == 0) {
say " no capture groups";
next;
}
unless (#captures) {
say " no match";
next;
}
# debug-output
for my $i ( 1 .. $#- ) {
say sprintf " \$%d - %s", $i, $captures[ $i - 1 ];
}
say sprintf $testHash{$pattern}, #captures;
}
I included four examples:
The first pattern is the one you had. It uses %1$s and so on as explained above.
The second one does not match. We check the number of elements in #captured by looking at it in scalar context.
The third one shows that you can also reorder the result, or even use the sprintf formatting.
The last one has no capture group. We check by looking at the index of the last element ($# as the sigil for arrays that usually have an # sigil) in #+, which holds the offsets of the ends of the last successful submatches in the currently active dynamic scope. The first element is the end of the overall match, so if this only has one element, we don't have capture groups.
The output for me is this:
pattern: (?^:(\d+)/(\d+)/(\d\d\d\d))
$1 - 1
$2 - 12
$3 - 2016
2016-12-01
pattern: (?^:(\d+)/(\d+)/(\d+) nomatch)
no match
pattern: (?^:\d)
no capture groups
pattern: (?^:(\d+)/(\d+)/(\d+))
$1 - 1
$2 - 12
$3 - 2016
1.12.2016
Note that the order in the output is mixed up. That's because hashes are not ordered in Perl, and if you iterate over the keys in a hash without sort the order is random.
Apologies! I realized both my question and sample code were both vague. But after reading your suggestions I came of with the following code.
I haven't optimized this code yet and there is a limit to the replacement.
foreach my $key (keys %testHash) {
if ( $str =~ $key ) {
my #matchArr = ($str =~ $key); # Capture all matches
# Search and replace (limited from $1 to $9)
for ( my $i = 0; $i < #matchArr; $i++ ) {
my $num = $i+1;
$testHash{$key} =~ s/\$$num/$matchArr[$i]/;
}
$result = $testHash{$key};
last;
}
}
print "$result\n";
Evaluing the regexp in list context returns the matches. so in your example:
use Data::Dumper; # so we can see the result
foreach my $pattern (keys (%testHash)) {
my #a = ($str =~/$pattern/);
print Dumper(\#a);
}
would do the job.
HTH
Georg
Is it also possible to store captured regex patterns in an array?
Of course it is possible to store captured substrings in an array:
#!/usr/bin/env perl
use strict;
use warnings;
my #patterns = map qr{$_}, qw{
(\d+)/(\d+)/(\d+)
};
my $str = '1/12/2016';
foreach my $pattern ( #patterns ) {
my #captured = ($str =~ $pattern)
or next;
print "'$_'\n" for #captured;
}
Output:
'1'
'12'
'2016'
I do not quite understand what you are trying to do with combinations of local, eval EXPR and eval BLOCK in your code and the purpose of the following hash:
my %testHash = (
'(\d+)\/(\d+)\/(\d+)' => '$1$2$3'
);
If you are trying to codify that this pattern should result in three captures, you can do that like this:
my #tests = (
{
pattern => qr{(\d+)/(\d+)/(\d+)},
ncaptures => 3,
}
);
my $str = '1/12/2016';
foreach my $test ( #tests ) {
my #captured = ($str =~ $test->{pattern})
or next;
unless (#captured == $test->{ncaptures}) {
# handle failure
}
}
See this answer to find out how you can automate counting the number of capture groups in a pattern. Using the technique in that answer:
#!/usr/bin/env perl
use strict;
use warnings;
use Test::More;
my #tests = map +{ pattern => qr{$_}, ncaptures => number_of_capturing_groups($_) }, qw(
(\d+)/(\d+)/(\d+)
);
my $str = '1/12/2016';
foreach my $test ( #tests ) {
my #captured = ($str =~ $test->{pattern});
ok #captured == $test->{ncaptures};
}
done_testing;
sub number_of_capturing_groups {
"" =~ /|$_[0]/;
return $#+;
}
Output:
ok 1
1..1
Have this string:
ABC,-0.5,10Y,10Y,['TEST'],ABC.1000145721ABC,-0.5,20Y,10Y,['TEST'],ABC.1000145722
The data is repeated.
I need to remove the []' characters from the data so it looks like this:
ABC,-0.5,10Y,10Y,TEST,ABC.1000145721ABC,-0.5,20Y,10Y,TEST,ABC.1000145722
I'm also trying to split the data to assign it to variables as seen below:
my($currency, $strike, $tenor, $tenor2,$ado_symbol) = split /,/, $_;
This works for everything but the ['TEST'] section. Should I remove the []' characters first then keep my split the same or is there an easier way to do this?
Thanks
Something that's useful to know is this - that split takes a regex. (It'll even let you capture, but that'll insert into the returned list, which is why I've got (?: for non capturing groups)
I observe your data only has [' right next to the delimiter - so how about:
#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
while ( <DATA> ) {
chomp;
my #fields = split /(?:\'])?,(?:\[\')?/;
print Dumper \#fields;
}
__DATA__
ABC,-0.5,10Y,10Y,['TEST'],ABC.1000145721ABC,-0.5,20Y,10Y,['TEST'],ABC.1000145722
Output:
$VAR1 = [
'ABC',
'-0.5',
'10Y',
'10Y',
'TEST',
'ABC.1000145721ABC',
'-0.5',
'20Y',
'10Y',
'TEST',
'ABC.1000145722'
];
my $str = "ABC,-0.5,10Y,10Y,['TEST'],ABC.1000145721ABC,-0.5,20Y,10Y,['TEST'],ABC.1000145722";
$str =~ s/\['|'\]//g;
print $str;
output is
ABC,-0.5,10Y,10Y,TEST,ABC.1000145721ABC,-0.5,20Y,10Y,TEST,ABC.1000145722
Now you can split.
Clean up $ado_symbol after split:
$ado_symbol =~ s/^\['//;
$ado_symbol =~ s/'\]$//;
You can use a global regex match to find all substrings that are not a comma, a single quote, or a square bracket
Like this
use strict;
use warnings 'all';
my $s = q{ABC,-0.5,10Y,10Y,['TEST'],ABC.1000145721ABC,-0.5,20Y,10Y,['TEST'],ABC.1000145722};
my #data = $s =~ /[^,'\[\]]+/g;
my ( $currency, $strike, $tenor, $tenor2, $ado_symbol ) = #data;
print "\$currency = $currency\n";
print "\$strike = $strike\n";
print "\$tenor = $tenor\n";
print "\$tenor2 = $tenor2\n";
print "\$ado_symbol = $ado_symbol\n";
output
$currency = ABC
$strike = -0.5
$tenor = 10Y
$tenor2 = 10Y
$ado_symbol = TEST
Another alternative
my $str = "ABC,-0.5,10Y,10Y,['TEST'],ABC.1000145721ABC,-0.5,20Y,10Y,['TEST'],ABC.1000145722";
my ($currency, $strike, $tenor, $tenor2,$ado_symbol) = map{ s/[^A-Z0-9\.-]//g; $_} split ',',$str;
print "$currency, $strike, $tenor, $tenor2, $ado_symbol",$/;
Output is:
ABC, -0.5, 10Y, 10Y, TEST
I thought this should be simple, matching strings in double/single quotes on same line
for example, following string all on same line
"hello" 'world' 'foo' "bar"
I have
print /(".*?")|('.*?')/g;
but I got following errors
Use of uninitialized value in print at ...
The following will return the warnings you mention:
use strict;
use warnings;
my $str = q{"hello" 'world' 'foo' "bar"};
print $str =~ /(".*?")|('.*?')/g;
That is because your regex will only match either one or the other of capture groups. The other one will not match and so will return undef.
The following will demonstrate:
while ($str =~ /(".*?")|('.*?')/g) {
print "one = " . (defined $1 ? $1 : 'undef') . "\n";
print "two = " . (defined $2 ? $2 : 'undef') . "\n";
print "\n";
}
Outputs:
one = "hello"
two = undef
one = undef
two = 'world'
one = undef
two = 'foo'
one = "bar"
two = undef
To get your desired behavior, just put the capture group around the entire expression.
print $str =~ /(".*?"|'.*?')/g;
You might want to check Text::ParseWords
use Text::ParseWords;
my $s = q{"hello" 'world' 'foo' "bar"};
my #words = quotewords('\s+', 0, $s);
use Data::Dumper; print Dumper \#words;
output
$VAR1 = [
'hello',
'world',
'foo',
'bar'
];
anoher option using backreference:
use strict;
use warnings;
my $str = q{"hello" 'world' 'foo' "bar"};
while ($str =~ /(["']).*?\1/g) {
print $& . "\n";
}