basic question help with strings

new to perl not a clue how cant find example

$a = ("ab ab ab ab ab"
$b = ("ab")
$times = # count how many times $b is in
$a

a simple 1 liner for sombody who knows ?

thanks darren

Re: basic question help with strings

Darren & Linda Ingall wrote:
> new to perl not a clue how cant find example
>
> $a = ("ab ab ab ab ab"
> $b = ("ab")
> $times = # count how many times $b is in
> $a
>
> a simple 1 liner for sombody who knows ?

perldoc -q "How can I count the number of occurrences of a substring within a
string"


John
--
use Perl;
program
fulfillment

Re: basic question help with strings

thanks i found that last night # still not got a clue
#!user/bin/perl -w
$count =0;
$me = "-";
$string = "-954548-2ab4abababab23 -76 4 1-4 -44";
while ($string =~ /$me\d+/g) { $count++ }
print $count

all the time $me = '-' it works but if i want $me to = "ab" no go
can sombody please explain

=~ /$me\d+/g

Re: basic question help with strings

Darren & Linda Ingall wrote:
> thanks i found that last night # still not got a clue
> #!user/bin/perl -w
> $count =0;
> $me = "-";
> $string = "-954548-2ab4abababab23 -76 4 1-4 -44";
> while ($string =~ /$me\d+/g) { $count++ }
> print $count
>
> all the time $me = '-' it works but if i want $me to = "ab" no go

Works exactly as expected for me. Seven instances of hyphen
followed by one or more digits. Two instances of "ab" followed
by one or more digits. (Also, it's "/usr" not "user".)

linux% cat test.pl
#!/usr/bin/perl -w
$string = "-954548-2ab4abababab23 -76 4 1-4 -44";
print "Checking string '$string'\n";
for $me ('-', 'ab') {
$count =0;
while ($string =~ /$me\d+/g) { $count++ }
print "For '$me', count = $count\n";
}
linux% ./test.pl
Checking string '-954548-2ab4abababab23 -76 4 1-4 -44'
For '-', count = 5
For 'ab', count = 2

> can sombody please explain
>
> =~ /$me\d+/g

=~ is the binding operator - used when searching/matching strings
in a variable other than $_.

//g finds all matches at once in list context, all matches
one at a time in scalar context (such as 'while()').

\d+ is something you should know already.

This is all explained on any decent tutorial on perl's regular
expressions operators. Which tutorial are you using?

-Joe

P.S. There is more traffic in comp.lang.perl.misc, although you
might find it overwhelming.

Re: basic question help with strings

Darren & Linda Ingall wrote:
> new to perl not a clue how cant find example
>
> $a = ("ab ab ab ab ab"
> $b = ("ab")
> $times = # count how many times $b is in
> $a
>
> a simple 1 liner for sombody who knows ?
>
perl -le '$x="ab ab ab";$me="ab";$x=~s/$me/$c++/eg;print $c'
3

you can use the /e to run a command instead of replacing

$x=~s/$me/$c++/eg

Rich


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