I want to check if number starts with 4 or 5 in CGI_问答_开发者

I want to check if number starts with 4 or 5 in CGI

开发者 https://www.devze.com 2023-01-30 09:10 出处：网络

I need to write some script in CGI which is new to me. I am trying to do if else with condition numbers starting with 5 or 开发者_如何学C6. So do one code if number starts with 5 and do another if num

use 5.013;
use warnings;
use Scalar::Util qw( looks_like_number );
use CGI;

my $param = CGI->new()->param('some_example');

given (substr $param, 0, 1) {
    when (! looks_like_number($_) ) { say 'Not a number'   }
    when (5)                        { say 'starts with 5'  }
    when (6)                        { say 'starts with 6'  }
}

Alternatively, rather than using substr to get the first letter, put $param and change (5) to your regex of choice.

I don't think you understand what CGI is. CGI is simply a set of environment variables that are set up by the webserver, and your program is executed with them. The output of the program becomes the webpage.

So if you want to write a CGI script in Python, PHP, C, Assembly, Whitespace... as long as it can be called and use environment variables, it's fine.

So this is really a language question. Which language are you using?

EDIT You specified Perl in a comment to this answer. I suggest you edit the question.

What's your input number? The Perl script will be run with a whole truckload of extra environment variables. Two of the most important are QUERY_STRING and REQUEST_METHOD. CGI consists of a specification of these environment variables, so any language can be used to write CGI.

Consider perl_cgi.cgi?something=else. The bit following the ? is the QUERY_STRING. You can specify this directly as part of an anchor:

<a href="perl_cgi.cgi?something=else">Run with something equals else</a>

or as part of a form (one of GET or POST, defaults to GET):

<form action="perl_cgi.cgi" method="[GET or POST]">
    <input type="text" name="something" value="else"/>
    <input type="submit" value="Submit!"/>
</form>

This will run your program with the same query string as above (or a different parameter, if the text box is changed) but REQUEST_METHOD will be either GET or POST depending.

So let's write a Perl CGI script to print the first number of the string we get (we're only passed strings):

use CGI;
$cgi=new CGI;
$x=$cgi->param('x');
$firstnum=substr($x, 0, 1);
print "Content-type: text/html\n\n";

print <<"EOF";
<html>
<head>
<title>My sample HTML page</title>
</head>
<body>
<p>The first number of $x is $firstnum</p>
</body>
</html>
EOF

This presupposes that this program is run as [program_name]?x=[some string]. It's up to you to make sure that's the case.

That should give you enough. You can check firstnum to see if its 5 or 6, then do different things depending.