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Extracting Whitespaces HTML/CGI (really easy)

Posted on 2003-11-30
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Last Modified: 2010-03-04
(this is more of an html/cgi problem i guess)

How do i extract whitespaces from a TEXTAREA and count how many characters there are?



Thanks,
Ben
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Question by:NeoHacker
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by:jmcg
ID: 9845412
Please explain some more about what you are asking.

When your CGI script receives the request from the user's browser, the form variables, including the TEXTAREA will be accessible (if you are using the CGI module, as you probably should) as

$txt = param('name_of_text_area');

The character count you are after may be as simple as "length($txt)". As for extracting whitespaces, you need to explain: are you asking how to remove _extra_ whitespace from the TEXTAREA, such as trimming extra spaces from the front and end? Or double spaces between words? Or what?
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by:ahoffmann
ID: 9846204
use CGI;
my $q = new CGI;
$txt=param('name_of_text_area');
$txt=~s/\s//g;@n=split(//,$txt)
print scalar @n;
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by:jmcg
ID: 9846297
Ahoffman,

Okay, that's an interpretation: how many non-whitespace characters are there in the TEXTAREA? But why go through all those gyrations to get something that's equivalent to

print length($txt);

(I wonder if that needs a \n on the end?).
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by:ahoffmann
ID: 9846338
hmm, probably folloing what is asked for:
  $txt=~s/[^\s]//g;@n=split(//,$txt);

depending on interpretation of "extract whitespaces" ;-)
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by:NeoHacker
ID: 9894107
sorry, i didnt mean EXTRACT them, i meant keep the whitespaces but COUNT the characters WITHOUT INCLUDING the whitespaces.
- i hope that clears thing up
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by:jmcg
ID: 9894145
Okay, Ahoffman had it right.

One recommended way to count characters is to use the 'tr' operator.

$count = $string =~ tr/ \t\r\n//c;

This does not actually change $string, but it counts all characters in the complement of the set specified as space, tab, carriage return, and line feed.
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ahoffmann earned 70 total points
ID: 9895205
($x=$txt)=~s/\s//g;
print scalar split(//,$x);
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by:jmcg
ID: 9898361
Ahoffman, I don't want to criticize, but why do you take the extra (and expensive) step of splitting a string into an array of single characters just to count them? The number of characters in the string will always be more cheaply obtained using 'length'. Am I missing something?
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by:ahoffmann
ID: 9898928
> .. don't want to criticize
don't worry, I'm learning too, sometimes, somehow ;-)
The extra step? you mean split? then you're correct.
But how about more perlish:
  $_=$txt; print tr/ \t\r\n//c;
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by:ozo
ID: 9900627
Ot if you don't want $_ to trash $_
  print tr/ \t\r\n//c for $txt;
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by:jmcg
ID: 9909991
Neohacker,

Hasn't your question been answered? I recommend that you accept one of Ahoffman's responses and close this question. Otherwise, if there's still something we can do for you, please ask.
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by:ahoffmann
ID: 9910976
BTW, when using split() in a scalar context, it does not generate an array
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by:NeoHacker
ID: 9917291
Ok, thanks ahoffman. Since you've helped me a lot on my questions, shouldn't i raise 20 points?

thanks,
ben
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