Re^2: Merge 2 strings like a zip [unzip()]

Based on my earlier zip(): this only uses substr.

#!/usr/bin/env perl -l

use strict;
use warnings;

print for unzip('AaBbCcDdEeFGHIJ', 5);

sub unzip {
    my ($str1, $len) = @_;

    my $str2 = '';

    for (0 .. $len - 1) {
        substr $str2, $_, 0, substr $str1, $_ + 1, 1, ''; 
    }

    return ($str1, $str2);
}
[download]

Output:

ABCDEFGHIJ
abcde
[download]

-- Ken

Comment on Re^2: Merge 2 strings like a zip [unzip()] Select or Download Code

Replies are listed 'Best First'.
Re^3: Merge 2 strings like a zip [unzip()] by tel2 (Pilgrim) on Jul 09, 2015 at 07:08 UTC
How dare you put us Kiwis to shame...again, Ken. Thanks again and keep up the good work! BTW, what's the 'for' for in: print for unzip...	[reply]
Re^4: Merge 2 strings like a zip [unzip()] by kcott (Archbishop) on Jul 09, 2015 at 14:18 UTC
You're welcome. Regarding the `for` statement modifier, I think ++hexcoder has covered most of this in his response. That's a fairly common Perl idiom that you're likely to see a lot. In fact, my usage wasn't the first in this thread: BrowserUk's zip() code has '`... for split '', $b;`'. There's a bit more going on behind the scenes. `for` iterates its list, aliasing `$_` to each item in turn (see perlsyn: Statement Modifiers for details) `print` defaults the filehandle to `STDOUT` and the list to the single item `$_` (that's true in this case but an oversimplification nonetheless: see print for the full story) The '`-l`' switch (on the shebang line) adds a `"\n"` to the end of each `print` statement (again, true in this case but still an oversimplification: see perlrun for the full details of '`-l`') `print for unzip('AaBbCcDdEeFGHIJ', 5);` [download] is equivalent to `for (unzip('AaBbCcDdEeFGHIJ', 5)) { print STDOUT "$_\n"; }` [download] -- Ken	[reply] [d/l] [select]
Re^5: Merge 2 strings like a zip [unzip()] by tel2 (Pilgrim) on Jul 10, 2015 at 00:39 UTC
Thanks for that explanation, Ken. I was aware of what "print for..." does (though I didn't realise some of the finer points you've mentioned), but I asked because I thought your code also worked without the 'for'. I now notice that the output without the 'for' has no newline between the returned arguments, i.e.: `ABCDEFGHIJabcde` which I assume is because it's just printing the 2 arguments (like a list) together. All that makes sense now though (I think), thanks. Sorry I wasn't clearer with my last question.	[reply] [d/l]
Re^6: Merge 2 strings like a zip [unzip()] by kcott (Archbishop) on Jul 10, 2015 at 04:35 UTC
Re^7: Merge 2 strings like a zip [unzip()] by tel2 (Pilgrim) on Jul 12, 2015 at 22:52 UTC
Re^4: Merge 2 strings like a zip [unzip()] by hexcoder (Curate) on Jul 09, 2015 at 08:09 UTC
`print for unzip('AaBbCcDdEeFGHIJ', 5);` could be written more explicitly also as `for (unzip('AaBbCcDdEeFGHIJ', 5)) { print $_; }` [download] The Perl documentation mentions this here: Statement Modifiers	[reply] [d/l] [select]
Re^5: Merge 2 strings like a zip [unzip()] by Anonymous Monk on Jul 09, 2015 at 08:24 UTC
print for unzip('AaBbCcDdEeFGHIJ', 5); could be written more explicitly also as for (unzip('AaBbCcDdEeFGHIJ', 5)) { print $_; } The Perl documentation mentions this here: Statement Modifiers I think you 're looking for verbosely in lieu of explicitly I could be wrong :)	[reply]


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