On Dec 6, Daniel Falkenberg said:
>What if $string does not meet the criteria in s/[^a-zA-Z0-9]+//g; can I
>get a print statement to say...
>
>if ($string ne s/[^a-zA-Z0-9]+//g) {
> print "$string does not meet our criteria...! Please try another
>password\n";
>}
You mean, "how can I see if a string contains invalid characters?"
This is an exercise from my book (chapter 2, "Simple Pattern Elements):
==========================================================================
8. Write a simple function that determines if the value given to it is a
valid hexadecimal number. Hexadecimal numbers have digits from 0 to 9,
and then from "A" to "F" (in upper- or lower-case). Does your function
accept the empty string has a hexadecimal number? If so, fix it so that
it does not.
==========================================================================
And here is the solution given:
==========================================================================
8. Here's the first approach, which ends up matching the empty string:
# if $num does NOT contain a
# character other than a-f, 0-9
# it is an OK hex number
if ($num !~ /[^a-f0-9]/i) { ... }
The reason that accepts an empty string is because an empty string doesn't
contain a character outside of the required character set. That being
said, there are many ways to make sure our string is not empty:
# here, ... represents our regex from above
# check for length
if (length($num) and ...) { ok }
# check against ''
if ($num ne '' and ...) { ok }
# match a valid character
if ($num =~ /[a-f0-9]/i and ...) { ok }
==========================================================================
I trust you can extrapolate that to your case. You want to make sure a
string contains ONLY the characters [A-Za-z0-9]. So use that in these
code examples instead of the hexadecimal class, [a-fA-F0-9].
You might notice I've used [a-f0-9] in these examples -- that's because I
have the /i modifier on, which means the regex is case-insensitive.
--
Jeff "japhy" Pinyan [EMAIL PROTECTED] http://www.pobox.com/~japhy/
RPI Acacia brother #734 http://www.perlmonks.org/ http://www.cpan.org/
** Look for "Regular Expressions in Perl" published by Manning, in 2002 **
<stu> what does y/// stand for? <tenderpuss> why, yansliterate of course.
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