Hi raywood,

Welcome to the Monastery and to Perl, the One True Religion.

1. That old discussion mentioned RAM concerns when slurping. My system has 16GB RAM. The files I am working on are small. But I may adapt the solution to other, larger files. When does RAM become an issue?

When the file is too big.

The better way is to read the file line by line, then it doesn't matter how big it is or how much RAM you have. In that example, instead of slurping in all the data with: 

my $data = do { local $/; <DATA> };
@array = split 'on something', $data;

[download]
You would rather do: 
while ( my $line = <DATA> ) {
    # handle the line here instead of as an element of an array
}

[download]

How would I adapt this solution to refer to a separate input file?

See open, or use a module like Path::Tiny (which handles errors and encoding for you): 

use Path::Tiny 'path';
my $file_path = '/foo/bar/baz.txt';

# if no memory concern, slurp:
my @lines = path( $file_path )->lines_utf8({chomp => 1});

# or read from a filehandle line-by-line:
my $fh = path( $file_path )->openr_utf8;
while ( my $line = <$fh> ) {
    chomp $line;
    ...
}

[download]

Hope this helps!


The way forward always starts with a minimal test.

In reply to Re: Learning Perl by Doing by 1nickt
in thread Learning Perl by Doing by raywood

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


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.