I am struggling to have a regex match for separating keys and values.
The requirement is that the delimiter is ':', yet the keys can have multiple "::". The values can have ':', but the keys cannot. So the first ':' should be the delimiter. If there is any space before the values, it should be eliminated.
I have the following regex, but it fails for key:value (no space after ':').
if ($_ =~ /^(.+?):\s+(.*)$/)
{
$data{$1} = $2;
}
Valid key values are:
key:value
key: value
key: value::subvalue
key::subkey:value
key::subkey:value:subvalue
key::subkey: value:subvalue
key::subkey::subsubkey:value
Note that key, subkey, value, subvalue can be replaces by any word. My regex works for all, but the first one.
How can I fix it?
I can have an elsif and add another regex, but I wonder if I can have a single regex for the whole thing.
/^((?:[^:]+::)*[^:]+):(?!:)\s*(.*)$/
DEMO
You can use this pattern:
/^((?>[^:]+|::)+):\s*(.*)$/
Related
in my Perl script I want to do conditional search & replace using regular expression: Find a certain pattern, and if the pattern exists in a hash, then replace it with something else.
For example, I want to search for a combination of "pattern1" and "pattern2", and if the latter exists in a hash, then replace the combination with "pattern1" and "replacement". I tried the following, but it just doesn't do anything at all.
$_ =~ s/(pattern1)(pattern2)/$1replacement/gs if exists $my_hash{$2};
I also tried stuff like:
$_ =~ s/(pattern1)(pattern2) && exists $my_hash{$2}/$1replacement/gs;
Also does nothing at all, as if no match is found.
Can anyone help me with this regex problem? Thx~
I would do it a different way. It looks like you have a 'search this, replace that' hash.
So:
#!/usr/bin/env perl
use strict;
use warnings;
#our 'mappings'.
#note - there can be gotchas here with substrings
#so make sure you anchor patterns or sort, so
#you get the right 'substring' match occuring.
my %replace = (
"this phrase" => "that thing",
"cabbage" => "carrot"
);
#stick the keys together into an alternation regex.
#quotemeta means regex special characters will be escaped.
#you can remove that, if you want to use regex in your replace keys.
my $search = join( "|", map {quotemeta} keys %replace );
#compile it - note \b is a zero width 'word break'
#so it will only match whole words, not substrings.
$search = qr/\b($search)\b/;
#iterate the special DATA filehandle - for illustration and a runnable example.
#you probably want <> instead for 'real world' use.
while (<DATA>) {
#apply regex match and replace
s/(XX) ($search)/$1 $replace{$2}/g;
#print current line.
print;
}
##inlined data filehandle for testing.
__DATA__
XX this phrase cabbage
XX cabbage carrot cabbage this phrase XX this phrase
XX no words here
and this shouldn't cabbage match this phrase at all
By doing this, we turn your hash keys into a regex (you can print it - it looks like: (?^:\b(cabbage|this\ phrase)\b)
Which is inserted into the substitution pattern. This will only match if the key is present, so you can safely do the substitution operation.
Note - I've added quotemeta because then it escapes any special characters in the keys. And the \b is a "word boundary" match so it doesn't do substrings within words. (Obviously, if you do want that, then get rid of them)
The above gives output of:
XX that thing cabbage
XX carrot carrot cabbage this phrase XX that thing
XX no words here
and this shouldn't cabbage match this phrase at all
If you wanted to omit lines that didn't pattern match, you can stick && print; after the regex.
What is wrong (as in not working) with
if (exists($h{$patt1)) { $text =~ s/$patt1$patt2/$patt1$1replacement/g; }
If $patt1 exists as a key in a hash then you go ahead and replace $patt1$patt2 with $patt1$replacement. Of course, if $patt1$patt2 is found in $text, otherwise nothing happens. Your first code snippet is circular, while the second one can't work like that at all.
If you want $patt1$patt2 first, and hash key as well then it seems that you'd have to go slow
if ($str =~ /$patt11$patt2/ && exists $h{$patt2}) {
$str =~ s/$patt1$patt2/$patt1$replacement/gs;
}
If this is what you want then it is really simple: you need two unrelated conditions, whichever way you turn it around. Can't combine them since it would be circular.
From the point of view of the outcome these are the same. If either condition fails nothing happens, regardless of the order in which you check them.
NOTE Or maybe you don't have to go slow, see Sobrique's post.
I have data that will appear as dual quotation pairs like this, per line.
"Key" "Value"
Inside of these pairs there can be any character, and sometimes there comes the
dreaded "" nested pair:
"Key "superkey"" ""Space" Value"
Previously I've found: "([^"]*)"\s*"([^"]*)"
And this matches Key and Value to two groups:
$1 = Key
$2 = Value
But, with the nested pairs, it will only output:
$1 = superkey
Is there a way to match all characters between the pairs? Example output wanted:
$1 = Key "superkey"
$2 = "Space" Value
Regular expression processing from QRegularExpression and c++11 Literal string:
QRegularExpression(R"D("([^"]*)"\s*"([^"]*)")D");
I know it matches Pearl and PHP regex.
"(.*?)"[\t\r ]+"(.*?)"(?=[ ]*$)
Try this.See demo.
https://regex101.com/r/hR7tH4/2
I want to match two string which differ only in element and newlines
$string1 = "perl is <match>scripting language</match>";
$string2 = "perl<TAG> is<TAG> scr<TAG>ipt<TAG>inglanguage";
Note: spaces and <TAG> and newline can come anywhere in string2. space may or may not present in string2 for e.g. in above instance in $string2 spaces between words scripting language is missing. we have to ignore space,tags,newline while matching string1 against string2. <match> tag in string1 indicates the data to be matched against string2
output required :
whole content of string2 in addition with <match> tag.
perl<TAG> is<TAG> <match>scr<TAG>ipt<TAG>inglanguage</match>
Code i tried :
while($string =~ /<match>(.*?)<\/match>/gs)
{
my $data_to_match = $1;
$data_to_match = add_pat($data_to_match);
$string2 =~ s{($data_to_match)}
{
"<match>$&<\/match>"
}esi;
}
sub add_pat
{
my ($data) = (#_);
my #array = split//,$data;
foreach my $each(#array)
{
$each = quotemeta $each;
$each = '(?:(<TAG>|\s)+)?'.$each.'(?:(<TAG>|\s)+)?';
}
$data = join '',#array;
return $data;
}
Problem : since space is missing in string2 it is not matching.i tried making space optional while appending pattern to each character. but making space optional. $string pattern goes on running.
In reality, i have large string to match. these space is causing problem..Please suggest
Use regular expressions to remove all the characters that you wish to ignore from both of the strings. Then compare the remaining values of the two strings.
So you will end up both strings, for example:
'perlisscriptinglanguage' and 'perlisscriptinglanguage'
If you want you can also upper/lower case them to match too.
If they match then just return the original string 2.
I think its weird that you are expected to "match". but $string2, if you take out the tags, doesnt match the original string.
Anyway, since your code is tolerant of Additional spaces and tags in $string2, then you can wipe all spaces (and tags if applicable) from $string1.
I added $data_to_match =~ s/ +//; before your call to add_pat. That didnt quite work because this line "$each = '(?:(|\s)+)?'.$each.'(?:(|\s)+)?';" adds the (?:(|\s)+)?' even before your first letter of the match from $string1. You actually have a lot of redundant TAG patterns, you add one to the front and back of each letter. I dont know what quotemeta does so im not sure how to fix the code there. I just added
$data_to_match =~ s/\Q(?:(<TAG>|\s)+)?\E//; line after the call to add_pat to strip off the first TAG pattern from the front of the pattern. otherwise it'll match wrong and output this 'perl < TAG> is< match>< TAG> scr< TAG>ipt< TAG>inglanguage< /match>'
Really you should only be putting one "(?:(|\s)+)?" inbetween each letter of the $string1 match, and more importantly; you should not be putting "(?:(|\s)+)?" before the first letter or after the last letter.
I have a question I am hoping someone could help with...
I have a variable that contains the content from a webpage (scraped using WWW::Mechanize).
The variable contains data such as these:
$var = "ewrfs sdfdsf cat_dog,horse,rabbit,chicken-pig"
$var = "fdsf iiukui aawwe dffg elephant,MOUSE_RAT,spider,lion-tiger hdsfds jdlkf sdf"
$var = "dsadp poids pewqwe ANTELOPE-GIRAFFE,frOG,fish,crab,kangaROO-KOALA sdfdsf hkew"
The only bits I am interested in from the above examples are:
#array = ("cat_dog","horse","rabbit","chicken-pig")
#array = ("elephant","MOUSE_RAT","spider","lion-tiger")
#array = ("ANTELOPE-GIRAFFE","frOG","fish","crab","kangaROO-KOALA")
The problem I am having:
I am trying to extract only the comma-separated strings from the variables and then store these in an array for use later on.
But what is the best way to make sure that I get the strings at the start (ie cat_dog) and end (ie chicken-pig) of the comma-separated list of animals as they are not prefixed/suffixed with a comma.
Also, as the variables will contain webpage content, it is inevitable that there may also be instances where a commas is immediately succeeded by a space and then another word, as that is the correct method of using commas in paragraphs and sentences...
For example:
Saturn was long thought to be the only ringed planet, however, this is now known not to be the case.
^ ^
| |
note the spaces here and here
I am not interested in any cases where the comma is followed by a space (as shown above).
I am only interested in cases where the comma DOES NOT have a space after it (ie cat_dog,horse,rabbit,chicken-pig)
I have a tried a number of ways of doing this but cannot work out the best way to go about constructing the regular expression.
How about
[^,\s]+(,[^,\s]+)+
which will match one or more characters that are not a space or comma [^,\s]+ followed by a comma and one or more characters that are not a space or comma, one or more times.
Further to comments
To match more than one sequence add the g modifier for global matching.
The following splits each match $& on a , and pushes the results to #matches.
my $str = "sdfds cat_dog,horse,rabbit,chicken-pig then some more pig,duck,goose";
my #matches;
while ($str =~ /[^,\s]+(,[^,\s]+)+/g) {
push(#matches, split(/,/, $&));
}
print join("\n",#matches),"\n";
Though you can probably construct a single regex, a combination of regexs, splits, grep and map looks decently
my #array = map { split /,/ } grep { !/^,/ && !/,$/ && /,/ } split
Going from right to left:
Split the line on spaces (split)
Leave only elements having no comma at the either end but having one inside (grep)
Split each such element into parts (map and split)
That way you can easily change the parts e.g. to eliminate two consecutive commas add && !/,,/ inside grep.
I hope this is clear and suits your needs:
#!/usr/bin/perl
use warnings;
use strict;
my #strs = ("ewrfs sdfdsf cat_dog,horse,rabbit,chicken-pig",
"fdsf iiukui aawwe dffg elephant,MOUSE_RAT,spider,lion-tiger hdsfds jdlkf sdf",
"dsadp poids pewqwe ANTELOPE-GIRAFFE,frOG,fish,crab,kangaROO-KOALA sdfdsf hkew",
"Saturn was long thought to be the only ringed planet, however, this is now known not to be the case.",
"Another sentence, although having commas, should not confuse the regex with this: a,b,c,d");
my $regex = qr/
\s #From your examples, it seems as if every
#comma separated list is preceded by a space.
(
(?:
[^,\s]+ #Now, not a comma or a space for the
#terms of the list
, #followed by a comma
)+
[^,\s]+ #followed by one last term of the list
)
/x;
my #matches = map {
$_ =~ /$regex/;
if ($1) {
my $comma_sep_list = $1;
[split ',', $comma_sep_list];
}
else {
[]
}
} #strs;
$var =~ tr/ //s;
while ($var =~ /(?<!, )\b[^, ]+(?=,\S)|(?<=,)[^, ]+(?=,)|(?<=\S,)[^, ]+\b(?! ,)/g) {
push (#arr, $&);
}
the regular expression matches three cases :
(?<!, )\b[^, ]+(?=,\S) : matches cat_dog
(?<=,)[^, ]+(?=,) : matches horse & rabbit
(?<=\S,)[^, ]+\b(?! ,) : matches chicken-pig
I have following text pattern
(2222) First Last (ab-cd/ABC1), <first.last#site.domain.com> 1224: efadsfadsfdsf
(3333) First Last (abcd/ABC12), <first.last#site.domain.com> 1234, 4657: efadsfadsfdsf
I want the number 1224 or 1234, 4657 from the above text after the text >.
I have this
\((\d+)\)\s\w*\s\w*\s\(\w*\/\w+\d*\),\s<\w*\.\w*\#\w*\.domain.com>\s\d+:
which will take the text before : But i want the one after email till :
Is there any easy regular expression to do this? or should I use split and do this
Thanks
Edit: The whole text is returned by a command line tool.
(3333) First Last (abcd/ABC12), <first.last#site.domain.com> 1234, 4657: efadsfadsfdsf
(3333) - Unique ID
First Last - First and last names
<first.last#site.domain.com> - Email address in format FirstName.LastName#sub.domain.com
1234, 4567 - database primary Keys
: xxxx - Headline
What I have to do is process the above and get hte database ID (in ex: 1234, 4567 2 separate ID's) and query the tables
The above is the output (like this I will get many entries) from the tool which I am calling via my Perl script.
My idea was to use a regular expression to get the database id's. Guess I could use regular expression for this
you can fudge the stuff you don't care about to make the expression easier, say just 'glob' the parts between the parentheticals (and the email delimiters) using non-greedy quantifiers:
/(\d+)\).*?\(.*?\),\s*<.*?>\s*(\d+(?:,\s*\d+)*):/ (not tested!)
there's only two captured groups, the (1234), and the (1234, 4657), the second one which I can only assume from your pattern to mean: "a digit string, followed by zero or more comma separated digit strings".
Well, a simple fix is to just allow all the possible characters in a character class. Which is to say change \d to [\d, ] to allow digits, commas and space.
Your regex as it is, though, does not match the first sample line, because it has a dash - in it (ab-cd/ABC1 does not match \w*\/\w+\d*\). Also, it is not a good idea to rely too heavily on the * quantifier, because it does match the empty string (it matches zero or more times), and should only be used for things which are truly optional. Use + otherwise, which matches (1 or more times).
You have a rather strict regex, and with slight variations in your data like this, it will fail. Only you know what your data looks like, and if you actually do need a strict regex. However, if your data is somewhat consistent, you can use a loose regex simply based on the email part:
sub extract_nums {
my $string = shift;
if ($string =~ /<[^>]*> *([\d, ]+):/) {
return $1 =~ /\d+/g; # return the extracted digits in a list
# return $1; # just return the string as-is
} else { return undef }
}
This assumes, of course, that you cannot have <> tags in front of the email part of the line. It will capture any digits, commas and spaces found between a <> tag and a colon, and then return a list of any digits found in the match. You can also just return the string, as shown in the commented line.
There would appear to be something missing from your examples. Is this what they're supposed to look like, with email?
(1234) First Last (ab-cd/ABC1), <foo.bar#domain.com> 1224: efadsfadsfdsf
(1234) First Last (abcd/ABC12), <foo.bar#domain.com> 1234, 4657: efadsfadsfdsf
If so, this should work:
\((\d+)\)\s\w*\s\w*\s\(\w*\/\w+\d*\),\s<\w*\.\w*\#\w*\.domain\.com>\s\d+(?:,\s(\d+))?:
$string =~ /.*>\s*(.+):.+/;
$numbers = $1;
That's it.
Tested.
With number catching:
$string =~ /.*>\s*(?([0-9]|,)+):.+/;
$numbers = $1;
Not tested but you get the idea.