how to insert all keys of array in database - php

Question

I have a array which always the number of its keys divided by 4 is integer (in oder words, mod is 0. for example in below example: [12 , 4] {div = 3 | mod = 0}).
My array is something like this:
$arr = Array
(
[0] => 'zero',
[1] => 'one',
[2] => 'two',
[3] => 'three',
[4] => 'four',
[5] => 'five',
[6] => 'six',
[7] => 'seven',
[8] => 'eight',
[9] => 'nine',
[10] => 'ten',
[11] => 'eleven'
);
Now I have a table with 4 column and I want to put all keys of my array into my table. In fact I want to insert each 4 keys of the array in 1 row of table. something like this:
// mytable
+---------+---------+---------+---------+
| col1 | col2 | col3 | col4 |
|---------------------------------------|
| zero | one | two | three |
| four | five | six | seven |
| eight | nine | ten | eleven |
+---------+---------+---------+---------+
I tried before asking and I concluded that I should use nested for(){}. Unfortunately, in reality my array has 1000 keys, and for this reason I can't do it manually. I know only the second for(){}:
for($i; I dont know the condition; $i++){
for ($j=0;$j<=3;$j++){ // selects 4 keys
$arr[$j];
}
INSERT INTO mytable VALUES ($arr[0],$arr[1],$arr[2],$arr[3]); // mysql codes
}
I know my codes are wrong, And please if you can help me. thanks

Answer 1

Actually you don't need a nested for. One is enough:
for ($j=0; $j<=count($array); $j+= ){ // selects 4 keys
INSERT INTO mytable VALUES ($arr[$j],$arr[$j+1],$arr[$j+2],$arr[$j+3]); // mysql codes
}
$j += 4; is the same as $j = $j + 4; it increases counter by 4.
Hope it helped :)