Re: validate chars for a string
[EMAIL PROTECTED] wrote:
> Since, everyone is so lively today, I'm going to push my luck today with
> this list. I need a little help here with validating a string to have only
> characters that I want, A-z and _ (underscore).
>
> So, this is what I'm stuck on:
In what way are you stuck?
>
>
> #should fail because of space
> $username="bob by";
>
> if(&isValidChars($username))
> ...
>
> #is there a better way but it isn't working anyway.
> sub isValidChars
> { my $retVal;
>
> @chars=split(//,$_[0]);
>
> for(@chars)
> {
> if($_ =~ /A-z/) { print "good [" . $_ . "]\n"; $retVal=1; }
> else { print "bad [" . $_ . "]\n"; $retVal=0; break; }
Where did you declare break. It is not part of the Perl language AFAIK.
>
> }
> return $retval;
> }
The best advice I can give is to always place
use strict;
use warnings;
before any other code in your script.
FWIW, last will serve the same function in Perl as break does in C.
Joseph
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Re: validate chars for a string
can you add a check length into a oneliner but w/o the $_[0]?
Also, is this correct and I guess to be consistent since the A-z test
didn't have the explicit reference to $_[0].:
sub isValidChars { return length($_[0]) > 4 && shift =~ /^[A-Za-z_.]+$/ }
> On Sep 29, [EMAIL PROTECTED] said:
>
>>Since, everyone is so lively today, I'm going to push my luck today with
>>this list. I need a little help here with validating a string to have
>> only
>>characters that I want, A-z and _ (underscore).
>
> You'll want to use a regular expression, or perhaps just the tr///
> operator.
>
>>sub isValidChars
>>{ my $retVal;
>>
>> @chars=split(//,$_[0]);
>>
>> for(@chars)
>> {
>>if($_ =~ /A-z/) { print "good [" . $_ . "]\n"; $retVal=1; }
>
> First, you probably mean /[A-z]/. Second, you probably mean /[A-Za-z_]/.
> Third, it's silly to do this character-by-character.
>
>>else { print "bad [" . $_ . "]\n"; $retVal=0; break; }
>
> "break" is spelled "last" in Perl.
>
>> }
>> return $retval;
>>}
>
> Here are a few variations:
>
> sub isValidChars {
> my $str = shift;
> if ($str =~ /^[A-Za-z_]+$/) { return 1 }
> else { return }
> }
>
> which can be written as simply
>
> sub isValidChars {
> return shift =~ /^[A-Za-z_]+$/;
> }
>
> and, in fact, the 'return' isn't necessary:
>
> sub isValidChars { shift =~ /^[A-Za-z_]+$/ }
>
> Or you could do the opposite: make sure the string DOESN'T have any
> ILLEGAL characters in it. The only problem with this is that an empty
> string is considered valid. That's why this approach includes a length()
> test.
>
> sub isValidChars {
> my $str = shift;
> return length($str) and $str !~ /[^A-Za-z_]/;
> }
>
> That returns true if and only if $str is non-zero in length and DOES NOT
> contain a NON-[A-Za-z_] character.
>
> Another way to do it is with tr///.
>
> sub isValidChars {
> my $str = shift;
> return length($str) and ($str =~ tr/A-Za-z_//c) == 0;
> }
>
> This time, we use length() again, but we use the tr/// operator, instead
> of the m// operator. The tr/// takes a character class, basically, and
> the /c modifier at the end means "take the opposite of this class". So
> $str =~ tr/A-Za-z_//c is scanning $str for any NON-[A-Za-z_] characters.
> tr/// returns the number of matching characters found. If the number of
> non-[A-Za-z_] characters is zero, and the length isn't zero, then it's a
> valid string.
>
> Which method should you use? I'd probably use the simplest form of the
> first isValidChars() I showed.
>
> --
> Jeff "japhy" Pinyan [EMAIL PROTECTED] http://www.pobox.com/~japhy/
> RPI Acacia brother #734 http://www.perlmonks.org/ http://www.cpan.org/
> what does y/// stand for? why, yansliterate of course.
> [ I'm looking for programming work. If you like my work, let me know. ]
>
>
> --
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
>
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Re: validate chars for a string
Lots of good stuff here. This oneliner is what makes perl cool but it's
like speaking in tongue -:)
> sub isValidChars { shift =~ /^[A-Za-z_]+$/ }
Thanks,
-rkl
> On Sep 29, [EMAIL PROTECTED] said:
>
>>Since, everyone is so lively today, I'm going to push my luck today with
>>this list. I need a little help here with validating a string to have
>> only
>>characters that I want, A-z and _ (underscore).
>
> You'll want to use a regular expression, or perhaps just the tr///
> operator.
>
>>sub isValidChars
>>{ my $retVal;
>>
>> @chars=split(//,$_[0]);
>>
>> for(@chars)
>> {
>>if($_ =~ /A-z/) { print "good [" . $_ . "]\n"; $retVal=1; }
>
> First, you probably mean /[A-z]/. Second, you probably mean /[A-Za-z_]/.
> Third, it's silly to do this character-by-character.
>
>>else { print "bad [" . $_ . "]\n"; $retVal=0; break; }
>
> "break" is spelled "last" in Perl.
>
>> }
>> return $retval;
>>}
>
> Here are a few variations:
>
> sub isValidChars {
> my $str = shift;
> if ($str =~ /^[A-Za-z_]+$/) { return 1 }
> else { return }
> }
>
> which can be written as simply
>
> sub isValidChars {
> return shift =~ /^[A-Za-z_]+$/;
> }
>
> and, in fact, the 'return' isn't necessary:
>
> sub isValidChars { shift =~ /^[A-Za-z_]+$/ }
>
> Or you could do the opposite: make sure the string DOESN'T have any
> ILLEGAL characters in it. The only problem with this is that an empty
> string is considered valid. That's why this approach includes a length()
> test.
>
> sub isValidChars {
> my $str = shift;
> return length($str) and $str !~ /[^A-Za-z_]/;
> }
>
> That returns true if and only if $str is non-zero in length and DOES NOT
> contain a NON-[A-Za-z_] character.
>
> Another way to do it is with tr///.
>
> sub isValidChars {
> my $str = shift;
> return length($str) and ($str =~ tr/A-Za-z_//c) == 0;
> }
>
> This time, we use length() again, but we use the tr/// operator, instead
> of the m// operator. The tr/// takes a character class, basically, and
> the /c modifier at the end means "take the opposite of this class". So
> $str =~ tr/A-Za-z_//c is scanning $str for any NON-[A-Za-z_] characters.
> tr/// returns the number of matching characters found. If the number of
> non-[A-Za-z_] characters is zero, and the length isn't zero, then it's a
> valid string.
>
> Which method should you use? I'd probably use the simplest form of the
> first isValidChars() I showed.
>
> --
> Jeff "japhy" Pinyan [EMAIL PROTECTED] http://www.pobox.com/~japhy/
> RPI Acacia brother #734 http://www.perlmonks.org/ http://www.cpan.org/
> what does y/// stand for? why, yansliterate of course.
> [ I'm looking for programming work. If you like my work, let me know. ]
>
>
> --
> To unsubscribe, e-mail: [EMAIL PROTECTED]
> For additional commands, e-mail: [EMAIL PROTECTED]
>
>
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Re: validate chars for a string
On Sep 29, [EMAIL PROTECTED] said:
>Since, everyone is so lively today, I'm going to push my luck today with
>this list. I need a little help here with validating a string to have only
>characters that I want, A-z and _ (underscore).
You'll want to use a regular expression, or perhaps just the tr///
operator.
>sub isValidChars
>{ my $retVal;
>
> @chars=split(//,$_[0]);
>
> for(@chars)
> {
>if($_ =~ /A-z/) { print "good [" . $_ . "]\n"; $retVal=1; }
First, you probably mean /[A-z]/. Second, you probably mean /[A-Za-z_]/.
Third, it's silly to do this character-by-character.
>else { print "bad [" . $_ . "]\n"; $retVal=0; break; }
"break" is spelled "last" in Perl.
> }
> return $retval;
>}
Here are a few variations:
sub isValidChars {
my $str = shift;
if ($str =~ /^[A-Za-z_]+$/) { return 1 }
else { return 0 }
}
which can be written as simply
sub isValidChars {
return shift =~ /^[A-Za-z_]+$/;
}
and, in fact, the 'return' isn't necessary:
sub isValidChars { shift =~ /^[A-Za-z_]+$/ }
Or you could do the opposite: make sure the string DOESN'T have any
ILLEGAL characters in it. The only problem with this is that an empty
string is considered valid. That's why this approach includes a length()
test.
sub isValidChars {
my $str = shift;
return length($str) and $str !~ /[^A-Za-z_]/;
}
That returns true if and only if $str is non-zero in length and DOES NOT
contain a NON-[A-Za-z_] character.
Another way to do it is with tr///.
sub isValidChars {
my $str = shift;
return length($str) and ($str =~ tr/A-Za-z_//c) == 0;
}
This time, we use length() again, but we use the tr/// operator, instead
of the m// operator. The tr/// takes a character class, basically, and
the /c modifier at the end means "take the opposite of this class". So
$str =~ tr/A-Za-z_//c is scanning $str for any NON-[A-Za-z_] characters.
tr/// returns the number of matching characters found. If the number of
non-[A-Za-z_] characters is zero, and the length isn't zero, then it's a
valid string.
Which method should you use? I'd probably use the simplest form of the
first isValidChars() I showed.
--
Jeff "japhy" Pinyan [EMAIL PROTECTED] http://www.pobox.com/~japhy/
RPI Acacia brother #734 http://www.perlmonks.org/ http://www.cpan.org/
what does y/// stand for? why, yansliterate of course.
[ I'm looking for programming work. If you like my work, let me know. ]
--
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
validate chars for a string
Since, everyone is so lively today, I'm going to push my luck today with
this list. I need a little help here with validating a string to have only
characters that I want, A-z and _ (underscore).
So, this is what I'm stuck on:
#should fail because of space
$username="bob by";
if(&isValidChars($username))
...
#is there a better way but it isn't working anyway.
sub isValidChars
{ my $retVal;
@chars=split(//,$_[0]);
for(@chars)
{
if($_ =~ /A-z/) { print "good [" . $_ . "]\n"; $retVal=1; }
else { print "bad [" . $_ . "]\n"; $retVal=0; break; }
}
return $retval;
}
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