Dear All:

For the indexed 1D array, I can easily use the following statements:


for ($index2 = 0; $index2 < $size; $index2++){
for ($index1 = $index2+1; $index1 < $size; $index1++)

to compare each distinct pair of the entires in the 1D array (the
upper triangle of the n*n square).

For the associative arrays, how can I do that?

Thanks.

Du

foreach

On Feb 16, 7:30 pm, Jer...@thebunnyshed.co.uk wrote:
> foreach

I know foreach. But using foreach how to do it?

You can get random access to keys using the array returned by
array_keys().

If it's the case that the arrays don't have the same keys or you can
have duplicate keys in an array (unlike your numerical array example),
then you can keep track of pairs that have already been seen, e.g.:

if (isset($seen[$k][$j])) continue;

$seen[$j][$k] = true;
$seen[$k][$j] = true;

On Feb 16, 12:49 am, "duzhid...@gmail.com" <duzhid...@gmail.com>
wrote:
> Dear All:
>
> For the indexed 1D array, I can easily use the following statements:
>
> for ($index2 = 0; $index2 < $size; $index2++){
> for ($index1 = $index2+1; $index1 < $size; $index1++)
>
> to compare each distinct pair of the entires in the 1D array (the
> upper triangle of the n*n square).
>
> For the associative arrays, how can I do that?
>
> Thanks.
>
> Du

Thanks. But if considering the efficiency of the PHP program, I think
foreach would be much faster. Right?



On Feb 16, 8:53 pm, petersprc <peters...@gmail.com> wrote:
> You can get random access to keys using the array returned by
> array_keys().
>
> If it's the case that the arrays don't have the same keys or you can
> have duplicate keys in an array (unlike your numerical array example),
> then you can keep track of pairs that have already been seen, e.g.:
>
> if (isset($seen[$k][$j])) continue;
>
> $seen[$j][$k] = true;
> $seen[$k][$j] = true;
>
> On Feb 16, 12:49 am, "duzhid...@gmail.com" <duzhid...@gmail.com>
> wrote:
>
> > Dear All:
>
> > For the indexed 1D array, I can easily use the following statements:
>
> > for ($index2 = 0; $index2 < $size; $index2++){
> > for ($index1 = $index2+1; $index1 < $size; $index1++)
>
> > to compare each distinct pair of the entires in the 1D array (the
> > upper triangle of the n*n square).
>
> > For the associative arrays, how can I do that?
>
> > Thanks.
>
> > Du

Dear petersprc:

If we use array_keys() to extract all keys, we just use the
traditional indexed array of keys to keep track of all pair of keys
from this 1D array, why bothering us to declare a new 2D array,
$seen[$j][$k]?




On Feb 16, 8:53 pm, petersprc <peters...@gmail.com> wrote:
> You can get random access to keys using the array returned by
> array_keys().
>
> If it's the case that the arrays don't have the same keys or you can
> have duplicate keys in an array (unlike your numerical array example),
> then you can keep track of pairs that have already been seen, e.g.:
>
> if (isset($seen[$k][$j])) continue;
>
> $seen[$j][$k] = true;
> $seen[$k][$j] = true;
>
> On Feb 16, 12:49 am, "duzhid...@gmail.com" <duzhid...@gmail.com>
> wrote:
>
> > Dear All:
>
> > For the indexed 1D array, I can easily use the following statements:
>
> > for ($index2 = 0; $index2 < $size; $index2++){
> > for ($index1 = $index2+1; $index1 < $size; $index1++)
>
> > to compare each distinct pair of the entires in the 1D array (the
> > upper triangle of the n*n square).
>
> > For the associative arrays, how can I do that?
>
> > Thanks.
>
> > Du

duzhidian@gmail.com wrote:
> Dear All:
>
> For the indexed 1D array, I can easily use the following statements:
>
>
> for ($index2 = 0; $index2 < $size; $index2++){
> for ($index1 = $index2+1; $index1 < $size; $index1++)
>
> to compare each distinct pair of the entires in the 1D array (the
> upper triangle of the n*n square).
>
> For the associative arrays, how can I do that?
>
> Thanks.
>
> Du
>

Du,

Something like:

$match = true;
if (count($array1) != count($array2)) {
$match = false;
else {
foreach ($array1 as $key->$value) {
if (!isset($array2[$key]) || $array2[$key] <> $value) {
$match = false;
break;
}
}
}



--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

Yeah, in the second case array_keys isn't applicable

$seen is needed if you're checking unique key pairs and there are no
restrictions on the array contents.

On Feb 16, 9:13 pm, "duzhid...@gmail.com" <duzhid...@gmail.com> wrote:
> Dear petersprc:
>
> If we use array_keys() to extract all keys, we just use the
> traditional indexed array of keys to keep track of all pair of keys
> from this 1D array, why bothering us to declare a new 2D array,
> $seen[$j][$k]?
>
> On Feb 16, 8:53 pm, petersprc <peters...@gmail.com> wrote:
>
> > You can get random access to keys using the array returned by
> > array_keys().
>
> > If it's the case that the arrays don't have the same keys or you can
> > have duplicate keys in an array (unlike your numerical array example),
> > then you can keep track of pairs that have already been seen, e.g.:
>
> > if (isset($seen[$k][$j])) continue;
>
> > $seen[$j][$k] = true;
> > $seen[$k][$j] = true;
>
> > On Feb 16, 12:49 am, "duzhid...@gmail.com" <duzhid...@gmail.com>
> > wrote:
>
> > > Dear All:
>
> > > For the indexed 1D array, I can easily use the following statements:
>
> > > for ($index2 = 0; $index2 < $size; $index2++){
> > > for ($index1 = $index2+1; $index1 < $size; $index1++)
>
> > > to compare each distinct pair of the entires in the 1D array (the
> > > upper triangle of the n*n square).
>
> > > For the associative arrays, how can I do that?
>
> > > Thanks.
>
> > > Du