G'day hellohello1,

Welcome to the monastery.

Here's a short script that tests solutions offered:

#!/usr/bin/env perl

use strict;
use warnings;

my @tests = ('0', '1', '000', '101', '010', '1 * 0 = 0');

my $format = '%9s | ' x 4 . "\n";

printf $format => qw{initial boundary start/end assign};

for (@tests) {
    my ($init, $bound, $start, $assign) = ($_) x 4;
    $bound =~ s/\b0\b/1/;
    $start =~ s/^0$/1/;
    $assign = 1 if $assign == 0;
    printf $format => $init, $bound, $start, $assign; 
}
[download]

Output:

  initial |  boundary | start/end |    assign | 
        0 |         1 |         1 |         1 | 
        1 |         1 |         1 |         1 | 
      000 |       000 |       000 |         1 | 
      101 |       101 |       101 |       101 | 
      010 |       010 |       010 |       010 | 
Argument "1 * 0 = 0" isn't numeric in numeric eq (==) at ./pm_example.
+pl line 16.
1 * 0 = 0 | 1 * 1 = 0 | 1 * 0 = 0 | 1 * 0 = 0 |
[download]

Results:

• Word boundaries fail with input like '1 * 0 = 0'
• Anchoring to the start and end of the string is successful in all instances
• Assignment conditional on equality to zero fails in two ways:
  1. A string that is not '0' but is evaluated as being numerically equal to zero (i.e. '000')
  2. A string that cannot be evaluated as being numeric generates a warning (i.e. '1 * 0 = 0')

So, with the data and solutions used here, only s/^0$/1/ works consistently.

You can change @tests to a list of representative examples from your data to get more realistic output. You can add tests for any other solutions that may present themselves.

Also, if you find more than one solution that works, and processing speed is important to you, you can compare them with Benchmark.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.