Beefy Boxes and Bandwidth Generously Provided by pair Networks
Do you know where your variables are?

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
I tried to get the first part of this code working but wasn't successful (see below). I had a problem using the map-function.
Can someone explain me why it doesn't work as presented here?
#!/usr/bin/perl -w use strict; #define your data: my %hash = ( .1 => 'url1', .2 => 'url2', .3 => 'url3', .7 => 'url7', .9 => 'url9', ); ## It works if I use this loop # my @good_keys; # foreach my $key ( keys %hash ) { # if ( $key > .4 ) { # push @good_keys, $key; # } # # } # but I can not get it to work with this map-function #define the fitness function / match determination my $good_value = sub { $_ > 0.4 }; #find the keys that match the fitness function: my @good_keys = map { $good_value->($_) } keys %hash; #now do something with the keys: ##eg. print the values, in hash order: for my $key (@good_keys) { print $hash{$key}, "\n"; }

In reply to Re^3: Hash table manipulation by GertMT
in thread Hash table manipulation by sarvan

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or or How to display code and escape characters are good places to start.
Log In?

What's my password?
Create A New User
Domain Nodelet?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others about the Monastery: (3)
As of 2021-11-27 06:39 GMT
Find Nodes?
    Voting Booth?

    No recent polls found