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Postings from May 2008
Rob Dixon wrote:
> Richard Lee wrote:
>
>> John W. Krahn wrote:
>>
>>
>>> Richard Lee wrote:
>>>
>>>
>>>> Can you please tell me how to shorten this?
>>>>
>>>> my @an = split(//);
>>>> my @num = grep { $_ eq ':' } @an ;
>>>>
>>>> I was trying to see how many : occur in variable but didn't know how
>>>> to do it fast so i did it like above...
>>>>
>>>> I would like to see as many way different ways to get this done if
>>>> possible
>>>>
>>>>
>>>> $var1 = root:x:123:/root:
>>>>
>>>> trying to see how many times : occurs in $var1..... and I could only
>>>> do it above way....
>>>>
>>> my $count = $var1 =~ tr/://;
>>>
>> Talking about reinventing the wheel!! thank you and I shall try this..
>> as I have nver tried tr before.......... thank you!!
>>
>
> tr/// is in the long tradition of Unix misnomers. It is comparable to s///g, but
> tr(anslates) characters in the first list to those in the second list, so
>
> $str =~ tr/;:/../;
>
> would replace all colons and semicolons with full stops. It returns the number
> of characters it has translated. However, if there is no character in the
> corresponding position in the second list the character remains unchanged but
> the count is still maintained, so
>
> $str =~ tr/://;
>
> returns the number of colons found but leaves them untouched. Similarly
>
> $str =? tr/\t /_/;
>
> translates all tabs to underscores, leaves spaces untouched, and returns the
> total number of either tab or spaces found in the object string.
>
> It is Perl idiom, and you should learn it.
>
> (If you want to be even more obscure then y/// is a synonym for tr///)
>
> HTH,
>
> Rob
>
this is great!!
use warnings;
use strict;
my $str = 'ab:cd:ef:g:hi::now;';
print $str =~ tr/:// . "\n";
print $str =~ tr/:b/_X/ . "\n";
print "$str\n";
././././././testthis.pl
6
7
aX_cd_ef_g_hi__now;
BTW, what is =? ? or is that a typo?
$str =? tr/\t /_/;
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