How to sort file based on line length including whitespace Perl

Question

Im trying to sort a file based on line length:

my name is tim
I like pineapples alot
hi

into something like this

hi
my name is tim
i like pineapples alot

I have to include whitespaces in there too, so what i have tried doing is putting each line into an array as one line = 1 string in the array. Then I tried to sort the array but that didnt work out too well.

Use a string length function for the comparison step of the sort function. — Dave S, Mar 21 '18 at 23:25
https://stackoverflow.com/questions/5917576/sort-a-text-file-by-line-length-including-spaces (there's a perl solution near the bottom) — zzxyz, Mar 21 '18 at 23:28
@zzxyz You talking about the one line thing that has perl in it? — yibs, Mar 21 '18 at 23:30
@yibs https://stackoverflow.com/a/46437608/58074 or https://stackoverflow.com/a/40786477/58074 yes — dsolimano, Mar 21 '18 at 23:32
@zzxyz im doing an assignment where I have to use a subroutine, i dont think it will count if i do that — yibs, Mar 21 '18 at 23:45
@yibs - Well, there are subroutines. 2 that you've created and are being called by 'the framework', and one that you've both created AND are calling implicitly in the call to `sort`. But it probably won't count if you have no idea how it works :) — zzxyz, Mar 21 '18 at 23:57
@zzxyz yea sorry im very new to this. All i was able to do is put each line into an array, so array index 1 would have the first line and so on. Im trying to figure out how to sort it so shortest line is in index 1 and longest is the last , including whitespaces :( — yibs, Mar 22 '18 at 00:02

score 0 · Answer 1 · answered Mar 22 '18 at 01:40

This (from one of the existing "duplicate" answers):

perl -ne 'push @a, $_; END{ print sort { length $a <=> length $b } @a }' file

And this:

#!/usr/bin/env perl

use warnings;
use strict;
my @arr;

sub compareLength
{
        length $::a <=> length $::b;
}

while (<>)
{
        push @arr, "$_";
}
print (sort {compareLength} @arr);

Are basically the exact same thing. -n creates the while(<>), END puts stuff after it, and the comparison function is anonymous (vs named) and inline. (But it still exists and is still a subroutine).

Oh, and I renamed @a to @arr, because I don't like two different variables both named a (@a and $a)

I hope this helps.

No need for all that `push`ing ☺ `perl -e 'print sort { length $a <=> length $b } <>' file` — haukex, Mar 22 '18 at 09:41
@haukex - Yeah, I deliberately picked a more....explicit? solution. Apparently barely slower, too, which I guess makes sense. — zzxyz, Mar 22 '18 at 15:43

How to sort file based on line length including whitespace Perl

1 Answers1