Regex Group in Perl: how to capture elements into array from regex group that matches unknown number of/multiple/variable occurrences from a string

groupingmatchperlregex

In Perl, how can I use one regex grouping to capture more than one occurrence that matches it, into several array elements?

For example, for a string:

var1=100 var2=90 var5=hello var3="a, b, c" var7=test var3=hello

to process this with code:

$string = "var1=100 var2=90 var5=hello var3=\"a, b, c\" var7=test var3=hello";

my @array = $string =~ <regular expression here>

for ( my $i = 0; $i < scalar( @array ); $i++ )
{
  print $i.": ".$array[$i]."\n";
}

I would like to see as output:

0: var1=100
1: var2=90
2: var5=hello
3: var3="a, b, c"
4: var7=test
5: var3=hello

What would I use as a regex?

The commonality between things I want to match here is an assignment string pattern, so something like:

my @array = $string =~ m/(\w+=[\w\"\,\s]+)*/;

Where the * indicates one or more occurrences matching the group.

(I discounted using a split() as some matches contain spaces within themselves (i.e. var3…) and would therefore not give desired results.)

With the above regex, I only get:

0: var1=100 var2

Is it possible in a regex? Or addition code required?

Looked at existing answers already, when searching for "perl regex multiple group" but not enough clues:

Best Solution

my $string = "var1=100 var2=90 var5=hello var3=\"a, b, c\" var7=test var3=hello";

while($string =~ /(?:^|\s+)(\S+)\s*=\s*("[^"]*"|\S*)/g) {
        print "<$1> => <$2>\n";
}

Prints:

<var1> => <100>
<var2> => <90>
<var5> => <hello>
<var3> => <"a, b, c">
<var7> => <test>
<var3> => <hello>

Explanation:

Last piece first: the g flag at the end means that you can apply the regex to the string multiple times. The second time it will continue matching where the last match ended in the string.

Now for the regex: (?:^|\s+) matches either the beginning of the string or a group of one or more spaces. This is needed so when the regex is applied next time, we will skip the spaces between the key/value pairs. The ?: means that the parentheses content won't be captured as group (we don't need the spaces, only key and value). \S+ matches the variable name. Then we skip any amount of spaces and an equal sign in between. Finally, ("[^"]*"|\S*)/ matches either two quotes with any amount of characters in between, or any amount of non-space characters for the value. Note that the quote matching is pretty fragile and won't handle escpaped quotes properly, e.g. "\"quoted\"" would result in "\".

EDIT:

Since you really want to get the whole assignment, and not the single keys/values, here's a one-liner that extracts those:

my @list = $string =~ /(?:^|\s+)((?:\S+)\s*=\s*(?:"[^"]*"|\S*))/g;
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