CODEWITHSUNDEEP
phpcodeigniter
Bakht
Bakht

Reputation: 113

How to Convert 2D array into 1D array?

I want to convert my 2D array into 1D array. When I do var_dump($image_name_db); It shows :

array(2) {
  [0]=>
  array(1) {
    ["image"]=>
    string(7) "pic.PNG"
  }
  [1]=>
  array(1) {
    ["image"]=>
    string(14) "abouttown3.jpg"
  }
}

Now how can I convert It into 1D array. As I want to compare two arrays. One array is 1D and other array is 2D, that is why i want 2D array in 1D. So i need both of them in 1D to compare easily. I am using codeigniter.

Upvotes: 4

Views: 3640

Answers (5)

mgrueter
mgrueter

Reputation: 1420

Why create a new problem when your original problem "How to compare two multidimensional arrays" can be solved easily?

If you really want to convert a multidimensional array into a single dimension, check out this post: Convert array of single-element arrays to a one-dimensional array

Upvotes: 0

Tamil Selvan C
Tamil Selvan C

Reputation: 20219

Use array_column() function for it, if php version is 5.5+

array_column($image_name_db, 'image');

See: http://php.net/manual/en/function.array-column.php

For below unsupported version use https://github.com/ramsey/array_column

if (!function_exists('array_column')) {
    /**
     * Returns the values from a single column of the input array, identified by
     * the $columnKey.
     *
     * Optionally, you may provide an $indexKey to index the values in the returned
     * array by the values from the $indexKey column in the input array.
     *
     * @param array $input A multi-dimensional array (record set) from which to pull
     *                     a column of values.
     * @param mixed $columnKey The column of values to return. This value may be the
     *                         integer key of the column you wish to retrieve, or it
     *                         may be the string key name for an associative array.
     * @param mixed $indexKey (Optional.) The column to use as the index/keys for
     *                        the returned array. This value may be the integer key
     *                        of the column, or it may be the string key name.
     * @return array
     */
    function array_column($input = null, $columnKey = null, $indexKey = null)
    {
        // Using func_get_args() in order to check for proper number of
        // parameters and trigger errors exactly as the built-in array_column()
        // does in PHP 5.5.
        $argc = func_num_args();
        $params = func_get_args();
        if ($argc < 2) {
            trigger_error("array_column() expects at least 2 parameters, {$argc} given", E_USER_WARNING);
            return null;
        }
        if (!is_array($params[0])) {
            trigger_error(
                'array_column() expects parameter 1 to be array, ' . gettype($params[0]) . ' given',
                E_USER_WARNING
            );
            return null;
        }
        if (!is_int($params[1])
            && !is_float($params[1])
            && !is_string($params[1])
            && $params[1] !== null
            && !(is_object($params[1]) && method_exists($params[1], '__toString'))
        ) {
            trigger_error('array_column(): The column key should be either a string or an integer', E_USER_WARNING);
            return false;
        }
        if (isset($params[2])
            && !is_int($params[2])
            && !is_float($params[2])
            && !is_string($params[2])
            && !(is_object($params[2]) && method_exists($params[2], '__toString'))
        ) {
            trigger_error('array_column(): The index key should be either a string or an integer', E_USER_WARNING);
            return false;
        }
        $paramsInput = $params[0];
        $paramsColumnKey = ($params[1] !== null) ? (string) $params[1] : null;
        $paramsIndexKey = null;
        if (isset($params[2])) {
            if (is_float($params[2]) || is_int($params[2])) {
                $paramsIndexKey = (int) $params[2];
            } else {
                $paramsIndexKey = (string) $params[2];
            }
        }
        $resultArray = array();
        foreach ($paramsInput as $row) {
            $key = $value = null;
            $keySet = $valueSet = false;
            if ($paramsIndexKey !== null && array_key_exists($paramsIndexKey, $row)) {
                $keySet = true;
                $key = (string) $row[$paramsIndexKey];
            }
            if ($paramsColumnKey === null) {
                $valueSet = true;
                $value = $row;
            } elseif (is_array($row) && array_key_exists($paramsColumnKey, $row)) {
                $valueSet = true;
                $value = $row[$paramsColumnKey];
            }
            if ($valueSet) {
                if ($keySet) {
                    $resultArray[$key] = $value;
                } else {
                    $resultArray[] = $value;
                }
            }
        }
        return $resultArray;
    }
}

or use array_map

$image_name_arr = array_map(function($arr){
   return $arr['image'];
},$image_name_db);

Upvotes: 2

n00dl3
n00dl3

Reputation: 21564

The best way is to use array_map, according to php doc:

array_map() returns an array containing all the elements of array1 after applying the callback function to each one. The number of parameters that the callback function accepts should match the number of arrays passed to the array_map()

example :

$output = array_map(function($current){
   return $current['image'];
},$your_array);

explanations :

The callback function receive the current element ($current) in the iterated array ($your_array, the 2D array) and returns the value to push to a new array (the output array is $output, it is a 1D array).

Upvotes: 1

Sougata Bose
Sougata Bose

Reputation: 31749

Try with - 

$array = array(array("image" => "pic.PNG"),  array("image" => "abouttown3.jpg"));
$new = array_map(function($arr) {
    return $arr['image'];
}, $array);

OutPut

array(2) {
  [0]=>
  string(7) "pic.PNG"
  [1]=>
  string(14) "abouttown3.jpg"
}

Upvotes: 1

Pupil
Pupil

Reputation: 23958

You need to traverse through the array and store images in to a 1D array.

<?php
$arr = array();
$arr[0]['image'] = 'pic.PNG';
$arr[1]['image'] = 'abouttown3.jpg';
$images = array();
if (! empty($arr)) {
  foreach ($arr as $row) {
    $images[] = $row['image'];
  }
}

echo "<br/> Existing";
echo '<pre>';
print_r($arr);
echo '</pre>';

echo "<br/> New";
echo '<pre>';
print_r($images);
echo '</pre>';

Working demo:

Upvotes: 1

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