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### Re: changing the position of an element in an array

by blazar (Canon)
 on Nov 17, 2005 at 13:29 UTC ( #509399=note: print w/ replies, xml ) Need Help??

```my \$pos;
for (0..\$#array) {
\$pos=\$_ and last
if \$array[\$_] eq \$wanted;
}
@array[\$pos,-1]=@array[-1,\$pos];

And what if no one of them matched? (Left as an exercise to the reader)

Update: it was a wonderfully neat solution (which is the reason why I posted it!) to another problem!!

Not just as neat:

```my \$pos;
for (0..\$#array) {
\$pos=\$_ and last
if \$array[\$_] eq \$wanted;
}
@array=@array[0..\$pos-1, \$pos+1..\$#array, \$pos];

And what if no one of them matched? (Left as an exercise to the reader ;-)

But then if you are sure in advance that one and only one element will match, here's a neat concise solution:

```@array=((grep \$_ ne \$wanted, @array), \$wanted);
You can patch it so that it works also if the above conditions are not verified, but won't be just as elegant. (Also left as an exercise to the reader!)

Solution:

```@array = do {
my \$i;
(grep \$i || \$_ ne \$wanted || \$i++, @array),
\$i ? \$wanted : ();
};

# or, as a sub:

sub move {
my (\$wanted, \$i)=shift;
(grep \$i || \$_ ne \$wanted || \$i++, @_),
\$i ? \$wanted : ();
}

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