Change multi dimensional array values

Question

I have an array like so

$dataArray = array(
    array( 20800, 21679, 0 ),
    array( 15254, 0, 3726 ),
    array( 17426, 2973, 0 ),
    array( 4391, 37, 0 ),
    array( 39194, 435, 0 )
);

If an array element is above 2000, I want to give it a value of 1. Else I want to give it a value of 0. So the above array should turn into

$dataArrayOutput = array(
    array( 1, 1, 0 ),
    array( 1, 0, 1 ),
    array( 1, 1, 0 ),
    array( 1, 0, 0 ),
    array( 1, 0, 0 )
);

What would be the best way to achieve this? At the moment I am trying

foreach ($dataArray as $data) {
    foreach ($data as $key => $value) {
        if($value > 1999) {
            $value = 1;
        } else {
            $value = 0;
        }
    }
}

But nothing seems to change. How can I achieve what I am after?

Thanks

Nigel Ren · Accepted Answer · 2018-10-10 19:31:17Z

2

More for entertainment value, but still a viable alternative. Using array_walk_recursive() to walk through the array structure, then if the item is an integer (is_int()) it will set it according to if it's > 1999 or not. If it's not an integer it just leaves the data as is.

array_walk_recursive($dataArray,  function (&$data) { 
            $data = (is_int($data))?(($data> 1999)?1:0):$data;    });

answered Oct 10, 2018 at 19:31

Nigel Ren

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1 Comment

Felippe Duarte Over a year ago

much more elegant solution

Madhur Bhaiya · Accepted Answer · 2018-10-10 19:23:48Z

1

Array values inside a foreach loop are passed by value. You can either explicity use & to pass values by reference, or, use the key to modify the original array. Try:

foreach ($dataArray as $key_out => $data) {
    foreach ($data as $key => $value) {
        if($value > 1999) {
            $dataArray[$key_out][$key] = 1;
        } else {
            $dataArray[$key_out][$key] = 0;
        }
    }
}

answered Oct 10, 2018 at 19:23

Madhur Bhaiya

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Comments

Felippe Duarte · Accepted Answer · 2018-10-10 19:35:26Z

1

You are close. You need to prepend a & to pass the memory address to the loop, and then update the value:

foreach ($dataArray as &$data) {
    foreach ($data as $key => &$value) {
        if($value > 1999) {
            $value = 1;
        } else {
            $value = 0;
        }
    }
}

You can read more about pass by reference here: http://php.net/manual/en/language.references.pass.php

If you have nested/different levels of your array, you can use a recursive function like this:

function recursiveUpdateValue($item) {
    if(is_array($item)) {
        foreach($item as $k => $v) {
            $item[$k] = recursiveUpdateValue($v);
        }
        return $item;
    } else {
        return ($item >= 2000) ? 1 : 0;
    }
}

$updatedArray = recursiveUpdateValue($dataArray);

edited Oct 10, 2018 at 19:35

answered Oct 10, 2018 at 19:21

Felippe Duarte

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Comments

Andreas · Accepted Answer · 2018-10-10 19:40:34Z

I understand this will be hard to read, but it's a short code.

I use array_intersect to find the zeros in your dataArray ($da).
Then I use array_replace with an array of [1,1,1] (by using array_fill) and overwrite what zeros I found.

$arr = [0,0,0];

foreach($dataArray as &$da){
    $da = array_replace(array_fill(0,count($da),1), array_intersect($da, $arr));
}

var_dump($dataArray);

Output

array(5) {
  [0]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(1)
    [2]=>
    int(0)
  }
  [1]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(0)
    [2]=>
    int(1)
  }
  [2]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(1)
    [2]=>
    int(0)
  }
  [3]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(1)
    [2]=>
    int(0)
  }
  [4]=>
  &array(3) {
    [0]=>
    int(1)
    [1]=>
    int(1)
    [2]=>
    int(0)
  }
}

https://3v4l.org/uaTcX

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