If you are regularly working with JSON, have you considered using JSON?

I realize there are times when one just wants something quick and dirty and throwaway. However, if this is more than a one-off throw-away need, devoting time to developing a collection of regexes to work with a well established streaming format seems to me a bit foolish. The code one writes will not have anywhere near the degree of long term reusability and reliability that a proper parsing module will.

For example, can you be sure that your arrays will always have only scalar elements? What about arrays nested in arrays? Arrays of hashes? That isn't even a question you need to worry about if you use a module that knows how to parse JSON in full.

(my $newnode = $node) =~ s/.*/[1,39,2,45]/s;
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I personally would forgot using s///.

my $newnode = '[1,39,2,45]';
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Wow, thanks for the fast reply!

I was thinking about using using s// as I will be reading in multiple file lines by line, e.g:

[-1,-1,-1,-1],[-1,-1,-1,-1],[-1,-1,-1,-1],[-1,-1,-1,-1],[-1,-1,-1,-1],[-1,-1,-1,-1],[-1,-1,-1,-1],[-1,-1,0,28],[0,27,0,29],[0,28,0,30]

and the details of the units for the replacements are contained in:

$node,e.g.

[-1,-1,0,28],

which will be replaced by other details contained in $newnode, e.g.

[1,30,2,34],

which is being uniquely generated on the fly.

I was wondering if there is a way to have an effect of say:

$line =~ s/$node/$newnode

After which $line is printed to an output file?

Thanks again!

Ardil:

I think I'll have to go with ELESHEVA on this one. Sure you could do it with regexes, but the JSON module doesn't seem to difficult to work with:

#!/usr/bin/perl
use strict;
use warnings;
use JSON;

while (my $line = <DATA>) {
    my $data = decode_json $line;
    if ($data->[0] == -1
        and $data->[1] == -1
        and $data->[2] == 32
        and $data->[3] == 45
    ) {
        $data = [ 1, 39, 2, 45 ];
    }
    print encode_json($data), "\n";
}
__DATA__
[-1,-1,32,45]
[-1,-1,-1,-1]
[-1,-1,0,28]
[0,27,0,29]
[0,28,0,30]
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On my machine, it produces (as expected):

$ perl 890521.pl
[1,39,2,45]
[-1,-1,-1,-1]
[-1,-1,0,28]
[0,27,0,29]
[0,28,0,30]
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Update: Fixed attribution.

...roboticus

When your only tool is a hammer, all problems look like your thumb.

$line =~ s/\Q$node/$newnode/
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