PHP iterate multi dimensional array with missing rows

Question

Suppose I have 2d array, where only some rows actually have some values in the columns, whereas other rows don't have anything.

For example: only rows 5 and 9 have some data, other rows are empty. Number of columns is fixed - 6

I have not declared any size for the 2D array.

I want to find all fields whose value is 10.

for ($t1=0; $t1 < count($array); $t1++) { 

    for ($t2=0; $t2 < 6; $t2++) { 

        if($array[$t1][$t2] == 10) {
            // do something
        }
    }
}

Now this code won't work because count($array) will be 2, so it will never iterate for rows 5 and 9.

I also need to get the index at which I found a match.

How can I write code to make it work in this case?

Lukasz032 · Accepted Answer · 2017-05-28 18:31:58Z

1

You can effectively use foreach in this case:

foreach($array as $s => $arrayElement) {
    for($t=0; $t<6; $t++) if ($arrayElement[$t] == 10) {
         // do something - $s is the row index, $t is the column index
    }
}

edited May 28, 2017 at 18:31

answered May 28, 2017 at 18:23

Lukasz032

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4 Comments

user5155835 Over a year ago

I tried using foreach, but could not write correct code. Can you write the complete code for this case?

Lukasz032 Over a year ago

In the internals of foreach loop you use $arrayElement as the direct pointer to your row (and thus you don't have to use an iterator for it). You don't use $array in the internals. (The internal loop will thus be single-dimensional traditional for loop - or you can replace even it with foreach if you do not need column index.)

user5155835 Over a year ago

I also need to get the index at which I found a match. How do I get the index?

Lukasz032 Over a year ago

I updated the code example to cover your case. The row index is assigned to $s.

mehfatitem · Accepted Answer · 2017-05-28 18:31:15Z

0

I think , you have a problem in defining array. May be , you can use this script.

<?php
$cars = array(
    array(
        "Volvo",
        22,
        18
    ),
    array(
        "BMW",
        15,
        13
    ),
    array(
        "Saab",
        5,
        2
    ),
    array(
        "Land Rover",
        17,
        15
    ),
    array(
        "Mercedes",
        22,
        19
    )
);

$length = count($cars);

for ($i = 0; $i < $length; $i++) {
    for ($j = 0; $j < 3; $j++) {
        echo $cars[$i][$j] . "</br>";
    }
}

?>

I hope , it will solve your problem.

answered May 28, 2017 at 18:31

mehfatitem

1471 silver badge12 bronze badges

1 Comment

Lukasz032 Over a year ago

It's about array with non-monotonic key values, so your example won't work as expected.

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