How can I append an array as an element to another array in PHP?

Question

So I have lots of arrays of the form:

$e = array( 
  "key1" => "value1",
  "key2" => "value2",
  "key3" => "value3",
  "key4" =? "value4"
);

And another array just declared as:

$a = array( );

What I want is to append $e to $a as an element, so

$a[0] = array( 
  "key1" => "value1",
  "key2" => "value2",
  "key3" => "value3",
  "key4" =? "value4"
);

So I can then go:

$count = count( $a );
for ( $j = 0; $j < $count; $j++ )
{
  echo $a[$j]["key1"];
}

and it will print "value1".

I will be repeating this process for all of the $e, so $a may not always be empty when the $e is appended - it may have had other $e appended previously. I thought that array_push would do this but it doesn't. Thanks for any help.

CaseySoftware · Accepted Answer · 2010-12-09 03:12:56Z

3

The quick and dirty way is pretty simple:

$a[] = $e;

and then do it again for any additional arrays. That will fill in the $a array starting with index zero and incrementing up.

If you wanted to use some sort of keys, you could do:

$a['firstarray'] = $e;

and accomplish much the same thing. The difference is that since keys must be unique, a screwup in that second method could overwrite an existing element. The first method has no chance of that happening.

answered Dec 9, 2010 at 3:12

CaseySoftware

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3 Comments

Jeremy Heslop Over a year ago

Also using $a[] instead of array_push is a tad faster for items less than 100k

Nilo Over a year ago

The $a[] method was the first thing I tried, before array_push, but that didn't work either. Anyway, I guess I'll work something out...

Nilo Over a year ago

LOL, it was a typo in my code, the $a[] method did work after all. I guess typos are a lot harder to make when using 1-letter variable names like in the example I gave above ;)

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