How to replace array value using a condition?

Question

Sorry for my title. I just don't know how to ask this. To make the story short I just need to replace a certain part of array. Let's say we have this array:

Array
(
      [0] => Array
        (
            [restaurant_id] => 1236
            [new_lat] => 76
            [new_long] => 86
            [date_updated] => 2013-11-15 17:20:58
        )

      [1] => Array
        (
            [restaurant_id] => 1247
            [new_lat] => 6
            [new_long] => 5
            [date_updated] => 2013-11-15 17:20:58
        )

      [2] => Array
        (
            [restaurant_id] => 7456
            [new_lat] => 21
            [new_long] => 12
            [date_updated] => 2013-11-15 17:20:58
        )

)

Now I need to replace the index 2 with this:

Array(
     [2] => Array
        (
            [restaurant_id] => 1236
            [new_lat] => 2
            [new_long] => 1
            [date_updated] => 2013-11-15 17:20:58
        )
)

I need to replace if I found out that there is an existing restaurant_id. If there is. Update that line. I not add the new array.

I have an idea but I don't know how to do this. My idea is:

Unserialize the array (because my array is in serialized form)
Find the target index. If found remove that index and add my new index to the bottom of array then serialize it again. If not found add only in the bottom of array and serialize.

I just dont know if I remove an index. If the index will be move automatically. Means If I delete index 2 the index 3 will became index 2 and my new array is index 3.

Ok that's all guys. thanks.

Is restaurant_id a unique ID for the entries?

Axel Amthor
– Axel Amthor

2013-11-15 09:51:00 +00:00
Commented Nov 15, 2013 at 9:51 — Axel Amthor
– Axel Amthor, Commented Nov 15, 2013 at 9:51

Stefanov.sm · Accepted Answer · 2013-11-15 09:57:04Z

2

Obtain a reference variable containing the target element and modify it.

foreach ($myArray as $myKey => &$myElement) 
{
 if ($myElement['restaurant_id'] == WHAT_IM_LOOKING_FOR)
 {
  $myElement['new_lat'] = ...;
  ...;
 }
}

answered Nov 15, 2013 at 9:57

Stefanov.sm

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Comments

Legionar · Accepted Answer · 2013-11-15 09:55:13Z

1

You dont have to remove that index; simply just overwrite it.

Unserialize
Find the target index. If found, just overwrite (not remove). If not found, simply add to the end with [].

Overwriting:

$my_array[2] = array(
    'restaurant_id' => 1236,
    'new_lat' => 2,
    'new_long' => 1,
    'date_updated' => '2013-11-15 17:20:58'
);

This code will overwrite your index 2 with this new. You dont need to unset it before.

edited Nov 15, 2013 at 9:55

answered Nov 15, 2013 at 9:50

Legionar

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5 Comments

Jerielle Over a year ago

Ok it is working now. But I am performing this in a loop. Does it affect if I perform this in a loop?

Legionar Over a year ago

Of course, you can check it in a loop, if its existing, overwrite; if not, just do array_push to the end of the array.

Jerielle Over a year ago

Sir can you help me with my code? I have a code that creates a textfiles. I can create a file. But I can't get the correct update.

Jerielle Over a year ago

Here's the link sir. stackoverflow.com/questions/19993642/…

Legionar Over a year ago

I can have a look on it.

Axel Amthor · Accepted Answer · 2013-11-15 09:59:10Z

if restaurant_id is a unique ID, it's quite easier to handle that array if you reorganize it a bit:

Array
(
      [1236] => Array
        (
            [new_lat] => 76
            [new_long] => 86
            [date_updated] => 2013-11-15 17:20:58
        )

      [1247] => Array
        (
            [new_lat] => 6
            [new_long] => 5
            [date_updated] => 2013-11-15 17:20:58
        )

      [7456] => Array
        (
            [new_lat] => 21
            [new_long] => 12
            [date_updated] => 2013-11-15 17:20:58
        )

)

after that you may find it easier to just access by

 ... isset($arr[$restaurantId]) ....

and

$arr[$restaurantId] = array('new_lat' => 42, .... )

will insert/update w/o any knowledge about whether the entry exists or not.

Hans Wassink · Accepted Answer · 2013-11-15 09:49:47Z

0

Ok, unset the element with the id, then resort, then add a new element:

    unset($array[2]); // unset number 2
    $array = array_values($array); // resort
    $array[] = $newStuff; // add

Good luck

answered Nov 15, 2013 at 9:49

Hans Wassink

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Comments

Theox · Accepted Answer · 2013-11-15 09:50:35Z

0

If you use the unset function, the index will stay empty.

For example, if your $array has 4 values, 0 1 2 3, if you unset index 2, the index 3 will stay 3, and new addition to the array will be index 4.

The following code will illustrate this :

$a = array("zero", "one", "two", "three");
var_dump($a);
unset($a[2]);
var_dump($a);
$a[]="four";
var_dump($a);

answered Nov 15, 2013 at 9:50

Theox

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4 Comments

Jerielle Over a year ago

It is working sir. But what if it is in a loop can I do the same? If i loop all the arrays values?

Theox Over a year ago

Yes, you can do the same, why not ? :)

Legionar Over a year ago

@Theox: why are you unseting it? Its not necessary... Simply overwrite it; see my answer below.

Theox Over a year ago

@Legionar : I'm simply answering Rochelle's question about deleting an index in an array. Indeed, in this case, as we want to update the array with new informations, overwriting the existing index is a good solution.

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