PHP: how to create associative array by key? - php

I have simple array
array(
array( 'id'=>5, 'something' => 2, 'dsadsa' => 'fsfsd )
array( 'id'=>20, 'something' => 2, 'dsadsa' => 'fsfsd )
array( 'id'=>30, 'something' => 2, 'dsadsa' => 'fsfsd )
)
How to create associative array by id field (or something else) from it in the right way?
array(
'5' => array( 'something' => 2, 'dsadsa' => 'fsfsd )
'20' => array( 'something' => 2, 'dsadsa' => 'fsfsd )
'30' => array( 'something' => 2, 'dsadsa' => 'fsfsd )
)

Something along these lines.
$new_array = array();
foreach ($original_array as &$slice)
{
$id = (string) $slice['id'];
unset($slice['id']);
$new_array[$id] = $slice;
}

#NikitaKuhta, nope. There is no slice function which returns a column of values in a 2D keyed table associated with a given key or column heading. You can use some of the callback array_... functions, but you will still need to execute a custom function per element so its just not worth it. I don't like Core Xii's solution as this corrupts the original array as a side effect. I suggest that you don't use references here:
$new_array = array();
foreach ($original_array as $slice) {
$id = (string) $slice['id'];
unset($slice['id']);
$new_array[$id] = $slice;
}
# And now you don't need the missing unset( $slice)

Related

sorting a multi dimensional array in php

I have an array of arrays, as such
$statuses = array(
[0] => array('id'=>10, 'status' => 'active'),
[1] => array('id'=>11, 'status' => 'closed'),
[2] => array('id'=>12, 'status' => 'active'),
[3] => array('id'=>13, 'status' => 'stopped'),
)
I want to be able to make a new array of arrays and each of those sub arrays would contain the elements based on if they had the same status.
The trick here is, I do not want to do a case check based on hard coded status names as they can be random. I want to basically do a dynamic comparison, and say "if you are unique, then create a new array and stick yourself in there, if an array already exists with the same status than stick me in there instead". A sample result could look something like this.
Ive really had a challenge with this because the only way I can think to do it is check every single element against every other single element, and if unique than create a new array. This gets out of control fast if the original array is larger than 100. There must be some built in functions that can make this efficient.
<?php
$sortedArray = array(
['active'] => array(
array(
'id' => 10,
'status' => 'active'
),
array(
'id' => 12,
'status' => 'active'
)
),
['closed'] => array(
array(
'id' => 11,
'status' => 'active'
)
),
['stopped'] => array(
array(
'id' => 13,
'status' => 'active'
)
),
)
$SortedArray = array();
$SortedArray['active'] = array();
$SortedArray['closed'] = array();
$SortedArray['stopped'] = array();
foreach($statuses as $Curr) {
if ($Curr['status'] == 'active') { $SortedArray['active'][] = $Curr; }
if ($Curr['status'] == 'closed') { $SortedArray['closed'][] = $Curr; }
if ($Curr['status'] == 'stopped') { $SortedArray['stopped'][] = $Curr; }
}
You can also do it with functional way though it's pretty the same like Marc said.
$sorted = array_reduce($statuses, function($carry, $status) {
$carry[$status['status']][] = $status;
return $carry;
}, []);

Counting distinct values in multidimensional array

I'm having real problems trying to figure this one out.
I have a PHP array which looks like this:
$info = array();
$info[0] = array(
'car' => 'Audi',
'previous_car' => 'BMW'
);
$info[1] = array(
'car' => 'Audi',
'previous_car' => 'Seat'
);
$info[2] = array(
'car' => 'Audi',
'previous_carg' => 'BMW'
);
$info[3] = array(
'car' => 'BMW',
'previous_car' => 'BMW'
);
$info[4] = array(
'car' => 'Ford',
'previous_car' => 'Seat'
);
I need to do some sorting on this, so the result looks like this:
Array (
car [
'Audi' => 3,
'BMW' => 1,
'Ford' => 1
],
previous_car [
'BMW' => 3,
'Seat' => 2
]
);
I need to count distinct occurrences of a value in the same key, but the search is made upon couple of arrays. I was trying to use array_value_count(), but I doesn't work well on multidimensional arrays.
I am trying to avoid the looping, since it can be overkill if the array is large.
I will be very grateful for all the help.
If you're running PHP 5.5, you can use:
$newArray = array(
'car' => array_count_values(array_column($info, 'car')),
'previous_car' => array_count_values(array_column($info, 'previous_car'))
);
var_dump($newArray);
For versions of PHP prior to 5.5
$newArray = array(
'car' => array_count_values(
array_map(
function($value) {
return $value['car'];
},
$info
)
),
'previous_car' => array_count_values(
array_map(
function($value) {
return $value['previous_car'];
},
$info
)
)
);
var_dump($newArray);
In a more object orientated way you can solve it as follows
$values = new ArrayObject();
$iterator = new RecursiveArrayIterator($info);
iterator_apply($iterator, 'countDistinct', array($iterator, $values));
function countDistinct($iterator, $values) {
while ( $iterator -> valid() ) {
if ( $iterator -> hasChildren() ) {
countDistinct($iterator -> getChildren(), $values);
} else {
if (!$values->offsetExists($iterator->key())) {
$values->offsetSet($iterator->key(), new ArrayObject());
}
if (!$values->offsetGet($iterator->key())->offsetExists($iterator->current())) {
$values->offsetGet($iterator->key())
->offsetSet($iterator->current(), 1);
} else {
$values->offsetGet($iterator->key())
->offsetSet($iterator->current(),
$values->offsetGet($iterator->key())->offsetGet($iterator->current()) + 1);
}
}
$iterator -> next();
}
}
Sure, with this example you do not avoid the loop. But with the ArrayObject and the RecursiveArrayIterator you will have some memory and performance advantages.
The result of this will exactly match your expected result, which you can easyliy iterate with the getIterator() function of the ArrayObject.
You can write a function that will sort your data but for now check this out:
http://www.php.net/manual/en/function.array-multisort.php
Here is what might help you:
$returnArray = array('car' => NULL, 'previous_car' => NULL);
foreach($info as $newInfo) {
$returnArray['car'][] = $newInfo['car'];
$returnArray['previous_car'][] = $newInfo['previous_car'];
}
$ret['car'] = array_count_values($returnArray['car']);
$ret['previous_car'] = array_count_values($returnArray['previous_car']);
var_dump($ret);
This returns:
array (size=2)
'car' =>
array (size=3)
'Audi' => int 3
'BMW' => int 1
'Ford' => int 1
'previous_car' =>
array (size=2)
'BMW' => int 3
'Seat' => int 2

multidimensional array - adding a key and value where a key and value is matched

I'm trying to add a key and value (associative) from an array to another array, where one specific key and value match. Here are the two arrays:
$array1 = array(
1 => array(
'walgreens' => 'location',
'apples' => 'product1',
'oranges' => 'product2'
),
2 => array(
'walmart' => 'location',
'apples' => 'product1',
'oranges' => 'product2',
'milk' => 'product3'
)
);
$array2 = array(
1 => array(
'walgreens' => 'location',
'apples' => 'product1',
'oranges' => 'product2',
'bananas' => 'product3',
)
);
Here is the attempt I made at modifying $array1 to have key 'bananas' and value 'product3':
$dataCJ = getCJItem($isbn);
foreach ($array1 as $subKey => $subArray) {
foreach($subArray as $dkey => $dval){
foreach($array2 as $cjk => $cjv){
foreach($cjv as $cjkey => $cjval){
if($dval['walgreens'] == $cjval['walgreens']){
$dval['bananas'] = $cjval['bananas'];
}
}
}
}
}
This doesn't work. How can I fix this?
Change => $dval to => &$dval. Currently you are creating and writing to a new variable and the update will not work in-place.
I would look at array_merge() function!
Here is a start with the PHP doc.
For your specific case, you could do the following :
foreach($array1 as $key1 => $values1){
foreach($array2 as $key2 => $values2){
if($values1[0] == $values2[0]){
$array1[$key1] = array_merge($values1, $values2);
}
}
}
Note to simplify the problem you should inverse the first key=> value pair of the array.
Having an array this way would be a lot simper :
array(
'location' => "The location (eg:walgreens)",
//...
);
This way you could change the comparison to the following instead :
$values1['location'] == $values2['location']
Which would be safer in the case the array is not built with the location as the first pair.

How to extract data out of a specific PHP array

I have a multi-dimensional array that looks like this:
The base array is indexed based on category ids from my catalog.
$cat[category_id]
Each base array has three underlying elements:
['parent_id']
['sort_order']
['name']
I want to create a function that allows us to create a list of category_id's and names for a given parent_category_id in the correct sort order. Is this possible? Technically it is the same information, but the array is constructed in a weird way to extract that information.
Here is an example definition for the array:
$cat = array();
$cat[32]['parent_id']= 0;
$cat[32]['sort_order']= 1;
$cat[32]['name']= 'my-category-name1';
$cat[45]['parent_id']= 0;
$cat[45]['sort_order']= 0;
$cat[45]['name']= 'my-category-name2';
$cat[2]['parent_id']= 0;
$cat[2]['sort_order']= 2;
$cat[2]['name'] = "my-category-name3";
$cat[3]['parent_id']= 2;
$cat[3]['sort_order']= 1;
$cat[3]['name'] = "my-category-name4";
$cat[6]['parent_id']= 2;
$cat[6]['sort_order']= 0;
$cat[6]['name'] = "my-category-name5";
Assuming it's something of this sort:
$ary = Array(
0 => Array(
'parent_category_id' => null,
'sort_order' => 0,
'name' => 'my-category-name0'
),
1 => Array(
'parent_category_id' => 0,
'sort_order' => 1,
'name' => 'my-category-name1'
),
2 => Array(
'parent_category_id' => 0,
'sort_order' => 2,
'name' => 'my-category-name2'
),
3 => Array(
'parent_category_id' => null,
'sort_order' => 0,
'name' => 'my-category-name3'
),
4 => Array(
'parent_category_id' => 3,
'sort_order' => 0,
'name' => 'my-category-name4'
)
);
You can use a combination of a foreach and usort to achieve what you're going for.
// #array: the array you're searchign through
// #parent_id: the parent id you're filtering by
function getFromParent($array, $parent_id){
$result = Array();
foreach ($array as $category_id => $entry){
if ($entry['parent_category_id']===$parent_id)
$result[$category_id] = $entry;
}
usort($result,create_function('$a,$b','return ($a["sort_order"]>$b["sort_order"]?1:($b["sort_order"]<$a["sort_order"]?-1:0));'));
return $result;
}
var_export(getFromParent($ary,0));
EDIT Sorry, fixed some syntax errors. Tested, and works (at least to result in what I was intending)
EDITv2 Here's the raw output from the above:
array (
0 =>
array (
'parent_category_id' => 0,
'sort_order' => 1,
'name' => 'my-category-name1',
),
1 =>
array (
'parent_category_id' => 0,
'sort_order' => 2,
'name' => 'my-category-name2',
),
)
(Used var_export just for you #FelixKling)
EDITv3 I've updated my answer to go along with the OP's update. I also now make it retain the original "category_id" values in the result array.
First you create an empty array, it will be used to store your result.
$result = array();
You need to iterate through your initial array, you can use foreach().
Then, given your parent_category_id simply use an if statement to check whether it's the given id or not.
If it is, just construct and push your result to your $result array.
Use any of the sort functions you like
Use the magic return $result;
You're done.
function returnSortedParents($categories, $target_parent){
$new_list = array();
foreach($categories as $index => $array){
//FIND ONLY THE ELEMENTS MATCHING THE TARGET PARENT ID
if($array['parent_category_id']==$target_parent){
$new_list[$index = $array['sort_order'];
}
return asort($new_list); //SORT BASED ON THE VALUES, WHICH IS THE SORTING ORDER
}

Matching an array value by key in PHP

I have an array of items:
array(
[0] => array(
'item_no' => 1
'item_name' => 'foo
)
[1] => array(
'item_no' => 2
'item_name' => 'bar'
)
) etc. etc.
I am getting another array from a third party source and need to remove items that are not in my first array.
array(
[0] => array(
'item_no' => 1
)
[1] => array(
'item_no' => 100
) # should be removed as not in 1st array
How would I search the first array using each item in the second array like (in pseudo code):
if 'item_no' == x is in 1st array continue else remove it from 2nd array.
// Returns the item_no of an element
function get_item_no($arr) { return $arr['item_no']; }
// Arrays of the form "item_no => position in the array"
$myKeys = array_flip(array_map('get_item_no', $myArray));
$theirKeys = array_flip(array_map('get_item_no', $theirArray));
// the part of $theirKeys that has an item_no that's also in $myKeys
$validKeys = array_key_intersect($theirKeys, $myKeys);
// Array of the form "position in the array => item_no"
$validPos = array_flip($validKeys);
// The part of $theirArray that matches the positions in $validPos
$keptData = array_key_intersect($theirArray, $validPos);
// Reindex the remaining values from 0 to count() - 1
return array_values($keptData);
All of this would be easier if, instead of storing the key in the elements, you stored it as the array key (that is, you'd be using arrays of the form "item_no => item_data") :
// That's all there is to it
return array_key_intersect($theirArray, $myArray);
You can also do:
$my_array =array(
0 => array( 'item_no' => 1,'item_name' => 'foo'),
1 => array( 'item_no' => 2,'item_name' => 'bar')
);
$thrid_party_array = array(
0 => array( 'item_no' => 1),
1 => array( 'item_no' => 100),
);
$temp = array(); // create a temp array to hold just the item_no
foreach($my_array as $key => $val) {
$temp[] = $val['item_no'];
}
// now delete those entries which are not in temp array.
foreach($thrid_party_array as $key => $val) {
if(!in_array($val['item_no'],$temp)) {
unset($thrid_party_array[$key]);
}
}
Working link
If your key is not actually a key of your array but a value, you will probably need to do a linear search:
foreach ($itemsToRemove as $itemToRemove) {
foreach ($availableItems as $key => $availableItem) {
if ($itemToRemove['item_no'] === $availableItem['item_no']) {
unset($availableItems[$key]);
}
}
}
It would certainly be easier if item_no is also the key of the array items like:
$availableItems = array(
123 => array(
'item_no' => 123,
'item_name' => 'foo'
),
456 => array(
'item_no' => 456,
'item_name' => 'bar'
)
);
With this you could use a single foreach and delete the items by their keys:
foreach ($itemsToRemove as $itemToRemove) {
unset($availableItems[$itemToRemove['item_no']]);
}
You could use the following to build an mapping of item_no to your actual array keys:
$map = array();
foreach ($availableItems as $key => $availableItem) {
$map[$availableItems['item_no']] = $key;
}
Then you can use the following to use the mapping to delete the corresponding array item:
foreach ($itemsToRemove as $itemToRemove) {
unset($availableItems[$map[$itemToRemove['item_no']]]);
}

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