array_intersect with unknown number of arrays

[Markus Ernst]

Hi

I have a question regarding array_intersect () in PHP 4.3. There are several
arrays created on the fly, such as:

$values['apples'];
$values['bananas'];
$values['pears'];

To extract only the values they have in common I tried this:

$command = "array_intersec t(";
for ($i=0; $i<count($value s); $i++) {
$command .= "\$values['$values[$i]'],";
}
$command = substr($command , 0, -1);
$command .= ");";
$result = eval($command);

This does not seem to work and also is quite complicated. Does somebody know
a better solution?

Thanks
Markus

[Steve]

Re: array_intersect with unknown number of arrays

[color=blue]
> I have a question regarding array_intersect () in PHP 4.3. There are several
> arrays created on the fly, such as:
>
> $values['apples'];
> $values['bananas'];
> $values['pears'];
>
> To extract only the values they have in common I tried this:
>
> $command = "array_intersec t(";
> for ($i=0; $i<count($value s); $i++) {
> $command .= "\$values['$values[$i]'],";
> }
> $command = substr($command , 0, -1);
> $command .= ");";
> $result = eval($command);
>
> This does not seem to work and also is quite complicated. Does somebody know
> a better solution?[/color]

The user comments in the docs for array_intersect suggest using
call_user_func_ array() to pass an arbitrary number of arguments.
Looks like you should be able to use:

$result = call_user_func_ array( 'array_intersec t', $values );

(untested, got to catch a bus!)

---
Steve

[Markus Ernst]

Re: array_intersect with unknown number of arrays

Steve wrote:
[...][color=blue]
> The user comments in the docs for array_intersect suggest using
> call_user_func_ array() to pass an arbitrary number of arguments.
> Looks like you should be able to use:
>
> $result = call_user_func_ array( 'array_intersec t', $values );[/color]

Works perfectly! I had even read this note, but as I did not understand the
examples provided I did not realize that it was what I looked for. Seems
like it's worth to have a closer look at PHP's function functions.

Thanks a lot for your input!

--
Markus