Re: Surprised by join

How about this myjoin function:

sub myjoin (&@) {
    my $sub = shift;
    my $res = $_[0];
    for my $i (1 .. $#_) {
    $res .= $sub->($_[$i-1], $_[$i]) . $_[$i];
    }
    $res;
}

my @a = (':','',':','');
my $i=0;
print myjoin { $a[$i++] } 0,1,0,1; # Right now
[download]

You can even change the separator depending of its neighbors, which are supplied as arguments to the code block.

Comment on Re: Surprised by join Download Code

Replies are listed 'Best First'.
Re^2: Surprised by join by EdwardG (Vicar) on Jun 08, 2004 at 13:47 UTC
++ I like this, although I'm starting to think that I had just misunderstood join and should probably go with an alternate solution rather than shoehorn join to my way of thinking.	[reply]
Re^3: Surprised by join by eserte (Deacon) on Jun 08, 2004 at 14:11 UTC
Somewhere else in this thread $a and $b were mentioned. The snippet above could be changed to use this. Instead of `$res .= $sub->($_[$i-1], $_[$i]) . $_[$i];` it would be `local $a = $_[$i-1]; local $b = $_[$i]; $res .= $sub->() . $_[$i];` [download] (Untested)	[reply] [d/l] [select]
Re^2: Surprised by join by Roy Johnson (Monsignor) on Jun 08, 2004 at 16:53 UTC
Your approach was exactly what the OP was looking for (++), but your example has some excess baggage that made it confusing for me. Simplified: `sub myjoin (&@) { my $sub = shift; my $res = shift; $res .= $sub->() . $_ for (@_); $res; }` [download] Update: Oh, I see: the arguments to sub were to stand in for $a and $b (a la sort), in case the user wanted to have that kind of flexibility in the sub. Is the thread title a C.S. Lewis reference, I wonder? The PerlMonk `tr///` Advocate	[reply] [d/l]
Re^3: Surprised by join by EdwardG (Vicar) on Jun 08, 2004 at 19:10 UTC
Is the thread title a C.S. Lewis reference, I wonder? It is, well spotted.	[reply]