About array array output related issues

About Array Output problems
The array structure is as follows

$a =array (' A ', ' B ', ' C ');
$a [0]=array (' AA ', ' ab ', ' AC ', ' ad ');
$a [1]=array (' AA ', ' ab ', ' AC ', ' ad ');

echo $a [2];

Output normal, Output C because $a[2] does not have an array defined.

How to enter a in one dimension.
echo $a [0];


------Solution--------------------
There's not a in one dimension.
He has been $a [0]=array (' AA ', ' ab ', ' AC ', ' ad '); Cover the

You Print_r ($a); I saw it.
------Solution--------------------
References:

There's not a in one dimension.
He has been $a [0]=array (' AA ', ' ab ', ' AC ', ' ad '); Cover the

You Print_r ($a); I saw it.

Positive solution
------Solution--------------------
$a =array (' A ', ' B ', ' C ');
$a [0]=array (' AA ', ' ab ', ' AC ', ' ad ');
After execution
$a = Array (
Array (' AA ', ' ab ', ' AC ', ' ad '),
' B ',
C
)
$a [1]=array (' AA ', ' ab ', ' AC ', ' ad ');
After execution
$a = Array (
Array (' AA ', ' ab ', ' AC ', ' ad '),
Array (' AA ', ' ab ', ' AC ', ' ad '),
C
)

So:
$a [0] = array (' AA ', ' ab ', ' AC ', ' ad ')
$a [1] = array (' AA ', ' ab ', ' AC ', ' ad ')
$a [2] = C

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