Match multiple words in a string ?

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Folks, How do I EXACTLY match a string (containing one or more words) with another string?
Example : Need to match
$str_to_find="Information received correctly"
from an array of strings @Output where string to match from can be :

$output[i]="The form Information recieved correctly on Tuesday".
[download]

So this would be the ONLY correct match. But
$output[j]="The Information from you was received today correctly "
is not considered a match. Also, following should not be matched (output found on different lines:

$output[1]="Information"
$output[1]="received"
$output[1]="correctly"
[download]

Any help is appreciated. Thanks in advance

Comment on Match multiple words in a string ? Select or Download Code

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Re: Match multiple words in a string ? by gaal (Parson) on Jul 23, 2004 at 21:57 UTC
Step one is the naive approach of searching with a regular expression: `@matches = grep /$str_to_find/, @Output; # WRONG` This gives you those strings that did match. But it breaks once $str_to_find contains data that is parsed as regexp metacharacter, since these modify the behavior of the match -- you can get both false positives and miss on true matches. So the solution is to `quotemeta $str_to_match` first, and match against that: `$quoted_str_to_match = quotemeta $str_to_match; @matches = grep /$quoted_str_to_match/, @Output;` [download] You can read up on quotemeta and \Q in perlre. Update: D'oh! TMTOWTDI, but friedo's way is much simpler in this case :-) Still, quotemeta/\Q are good to know about.	[reply] [d/l] [select]
Re: Match multiple words in a string ? by TrekNoid (Pilgrim) on Jul 23, 2004 at 22:12 UTC
As long as special characters aren't involved, shouldn't the following work? `foreach $output (@output) { if ($output =~ /$str_to_find/) { print "$output\n"; } }` [download] Trek	[reply] [d/l]
Re: Match multiple words in a string ? by friedo (Prior) on Jul 23, 2004 at 21:53 UTC
~~Use the substr function.~~ Pay no attention to the crazy man.	[reply]
Re^2: Match multiple words in a string ? by BrowserUk (Patriarch) on Jul 23, 2004 at 22:01 UTC
I think you mean the index function? Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "Think for yourself!" - Abigail "Memory, processor, disk in that order on the hardware side. Algorithm, algoritm, algorithm on the code side." - tachyon	[reply]
Re^3: Match multiple words in a string ? by friedo (Prior) on Jul 23, 2004 at 22:39 UTC
Doh! I really should refrain from posting when decaffeinated.	[reply]
Re: Match multiple words in a string ? by mifflin (Curate) on Jul 23, 2004 at 22:08 UTC
You can used grep to return an array of all the records that matched your string... `@matched = grep {/Information received correctly/} @output;` [download]	[reply] [d/l]