Push function in a For Loop to create many new arrays

Question

I'm new in Perl and appreciate much if someone can help me on this.

foreach $line(@resultans){
    my @newresultans = split "_",$line;

    ## i will have lots more of $newresultans and @ans
    push(@ans1, $newresultans[2]);
    push(@ans2, $newresultans[3]);
    ......
    ......

 }

My intention is to split something like this, and push them into many arrays.

12, 2, and so on in the following rows pushed into an array(@ans1). Same goes to 6, 7 (@ans2) and there are much more numbers after that,separated by _. which is to form @ans3, @ans4

2_abc_12_6_.......
2_def_2_7_......
.................

Can I try something like this? but it doesn't seem to work. I really appreciate a lot if someone can help me. Thanks!!

$ANS_name ="ANS_$colnm";

foreach $line(@resultans){
    my @newresultans = split "_",$line;

    for($colnm=0;$colnm <=$column[0] ; $colnm++){
        push(@$ANS_name, $newresultans[2]);
    }
}

TLP · Accepted Answer · 2014-01-12 15:03:18Z

It seems to me like what you are saying is that you have a variable amount of columns in each split, and you want a dynamic - rather than hard coded - way to store them. I think what you are looking for is an array or arrays:

my @all;
for my $line (@res) {
    my @new = split /_/, $line;   # split takes a regex, not a string (normally)
    for my $index (0 .. $#new) {
        push @{ $all[$index] }, $new[$index];
    }
}

Your idea about patching together variable names is quite bad, and you should avoid that. If for nothing else that it is exactly what a hash does, but you don't have to break any rules to use a hash. We could have used a hash here, but there was no point since your data was serial, and you had no fixed names. For example:

my %hash;
...
for my $index( 0 .. $#res ) {
    $ANS_name ="ANS_$index";
    push @{ $hash{$ANS_name} }, $new[$index];
}

amon · Accepted Answer · 2014-01-12 15:03:31Z

1

What you're asking is possible, but frowned upon. It is much better to use an array of arrays:

my @column;
for my $line (@resultans) {
  my (undef, undef, @parts) = split /_/, $line;  # discard first 2 elements
  push @{ $column[$_] }, $parts[$_] for 0 .. $#parts;
}

Then @column would be:

(
  [12, 2],
  [6, 7],
)

We can access the entries for the first column like @{ $column[0] }.

answered Jan 12, 2014 at 15:03

amon

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