index using a range

[romano]

I have a string composed of numbers. Is there a way to find the index for the first non-zero character 1-9? Can I do this directly? I know I can use 'pos' or substitute for non-zero values and then do index but is there a way to do that directly?

$Str1 = "000001";
$Index = index($Str1, [1-9]);
print "$Index\n";

This does not work.

grazie,

romano

[LanX]

> I know I can use pos or substitute for non-zero values and then do index but is there a way to do that directly?

pos is the way to do it directly.

  DB<111> $str1 = "000001";$str1 =~ m/[^0]/g; print pos($str1)
6

[choroba]

A bit cryptic, but without the need of $1:

my $str   = '000001';
my $index = length(($str =~ /^(0*)/)[0]);

[jwkrahn]

$ perl -le'
my $Str1 = "000001";
$Str1 =~ /[1-9]/ and my $Index = $-[ 0 ];
print "$Index\n";
'
5

[hdb]

A good application for the under-estimated comma operator:

$str = "000001";
$index = ( $str =~ /^(0*)/, length $1 );
print "$index\n";

[vsespb]

$Str1 = "000001";
print length($1) if $Str1 =~ /^(.*)[0-9]$/;

UPD:
Probably better /^(.*)[0-9]/; (without '$' in the end of regexp)

[rnewsham]

A slight variation on the solution proposed by vsespb, I think this is a little closer to what you want.

my $Str1 = "000001"; 
my $Index = length($1) if $Str1 =~ /^(0*)[1-9]$/; 
print "$Index\n"; 

[romano]

I was hoping I could incorporate the range ([0-9] or ^0) directly into the ‘index’ statement.

$Index – index($Str1, ‘the first non-zero value’);

but I guess not. So, it needs to be done in 2 statements.
thanks,
romano (aka KennB)

[farang]

Assuming the string is only numerals and isn't all zeros (which could be checked for separately), here's a method that uses coercion of a string into a number.

use strict;
use warnings;

for my $Str1 ( "987654", "087654", "007654", "000654", "000054", "0000
+04" ) {
        my $Index = length($Str1) - length($Str1 + 0) + 1;
        print "$Str1  pos=$Index\n";
}

__END__
987654  pos=1
087654  pos=2
007654  pos=3
000654  pos=4
000054  pos=5
000004  pos=6

[vsespb]

Most cryptic:

use List::Util qw/min/;
$Str1 = "000001";
print min grep { $_ >= 0 } map { index $Str1, $_ } 1..9;

[hbm]

$Str1 = "000001";
#$Index = index($Str1, [1-9]);
$Index  = @{[$Str1=~/(?<=0)./g]}+0;
print "$Index\n";

Update: Doesn't work for "001001", for example...

[trizen]

Using index with tr/// :

    perl -E 'say index("000001000"=~tr/0/1/cr, "1")' # says "5"