Printing Perl Hash Keys

perl hash printing key

47,647

Solution 1

Does this do it for you?

print "$_\n" for keys %hash;

Solution 2

Short version:

$, = "\n";
print keys %hash;

Or inside a larger script:

{
    local $, = "\n";
    print keys %hash;
}

To put it in a variable, for printing in a message box in accordance to your comments:

my $var = join "\n", keys %hash;

47,647

Author by

Dynamic

Updated on July 08, 2020

Comments

Dynamic almost 4 years

I am trying to print out my Hash Keys in Perl, one per line. How would I go about doing this?
Zaid almost 13 years

say for keys %hash; in post 5.10
Dynamic almost 13 years

Is there a way to put that into a Perl/Tk program?
Dynamic almost 13 years

Is there a way to put that inside of a Perl/Tk program?
Keith Thompson almost 13 years

@perl.j: It's straightforward Perl; why wouldn't it work in a Perl/Tk program?
Dynamic almost 13 years

Well I am trying to put it in as the text in a messageBox but it isn't working. Any suggestions?
TLP almost 13 years

@perl It's not really possible to answer such a question without seeing the code.
Dynamic almost 13 years

Well I would hate to put all that code in a comment show the area of concern: sub show_index { my $index = $mw->messageBox(-type=>"ok", -icon=>"info", -message=> -title=>"Index"); } The blank message area is where I want the code.
TLP almost 13 years

Put this in: join "\n", keys %hash. It's a very different question from the one you asked.
Dynamic almost 13 years

@TLP: Thank You so much. You're great! +1 for you!
musiKk almost 13 years

I don't think one should use $,. I mean, I like it too but I fear that most people would have to look it up.
TLP almost 13 years

Turns out, OP didn't want to print the keys at all, so the solution is the "join" thing, not the $, part. Besides, what's wrong with using such variables? They are there for a reason.
Dave Cross almost 8 years

The map function is there to transform a list. If you are using map in void context (i.e. if you're not using the return value) then you're using it wrong and should probably switch to using a foreach loop instead (for example print "$_\n" foreach keys %hash would work here). An alternative that uses map as intended might be print map { "$_\n" } keys %hash.