使用Perl正则表达式搜索并替换一定长度的字符串

Question

I am trying to search and replace a string that is up to and including 3 characters in length with nothing (so 'deleting' the element contents).

So I have something like:

foreach (@array) {
   s/^{1,3}$//;
}

Eg

@array = ('one', 'two', 'three', 'four', 'five', 'six', 'seven');

So when printing, expected output would be:

result:  result:  result: three  result: four  result: five  result:  result: seven

So for the affected inputs, the output would be an 'empty place'.

This at the moment doesn't happen... I'm betting I'm making a simple mistake due to my still-shaky understanding of regex. Any help appreciated!

If there is a simple way to actually remove the element totally without creating a new array, that would also be useful to know.

Answer 1

If you want to match any three characters, s/^.{1,3}$// should work. I just added a dot after the ^ , as your original regex didn't specify what kind of character you wanted to match 1-3 of.

Answer 2

Probably s/^\\w{1,3}$//;

You are forgetting \\w to group it with {1,3}

Answer 3

Simple regex problem aside, you can use grep to select the elements you want:

@array = grep { !/^.{1,3}$/ } @array;

Then just print the results:

print "Result: $_\n" foreach @array;

Results:

Result: three
Result: four
Result: five
Result: seven

Answer 4

The way I read your question is that you want to actually modify the array's contents. You could use splice thusly:

#!/usr/bin/env perl
use strict;
use warnings;
use Data::Dumper;
my @array = qw(one two three four five six seven);
my $i = 0;
for (@array) {
    m/^\w{1,3}$/ && splice(@array, $i, 1, undef);
    $i++;
}
print Dumper \@array;
print "\n";
for my $e (@array) {
    print defined $e ? "result: $e  " : "result:  "
}
print "\n";

And when run:

$VAR1 = [
          undef,
          undef,
          'three',
          'four',
          'five',
          undef,
          'seven'
        ];

result:  result:  result: three  result: four  result: five  result:  result: seven