Beefy Boxes and Bandwidth Generously Provided by pair Networks
"be consistent"

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??

This is a problem where it really, really pays off to familiarize with some Perl idioms. The other comments showed steps to get to a result beginning with the code - here's another approach beginning with your problem.

Whenever I see a for loop containing a push, the map function springs into my mind. Together with grep to remove unwanted elements from a list, the code collapses to a few lines (Note that I also dropped use feature qw/say/; because that comes automatically with use 5.10.1;):

#!/usr/bin/perl use strict; use warnings; use 5.10.1; my $all_the_numbers=int(rand(19)); my @rand = map { 20-int(rand(30)) } (1..$all_the_numbers); say "@rand"; @rand = grep { $_ < 0 } @rand; say "@rand";

The function map takes a list to the right (note how I wrote that list without a loop), and applies the code block to each of the elements, to create a new list. In our case, we just create a new random number per element.

The grep function checks a code block against each element of a list and returns a new list containing only those elements where the code block evaluates to a true value. $_ is Perl's magical variable which holds the current value of the list while walking through it (To be precise, it is an alias to the list element, but this doesn't matter in our case).

Edit: Fixed the grep condition as detected by hdb in Re^2: Deleting certein elements from an array. Thanks for spotting this!

In reply to Re: Deleting certein elements from an array by haj
in thread Deleting certein elements from an array by Eso

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 avoiding work at the Monastery: (2)
As of 2022-08-20 00:11 GMT
Find Nodes?
    Voting Booth?

    No recent polls found