如何将2D数组转换为1D数组？

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

我想将我的2D数组转换为1D数组。当我做var_dump($ image_name_db);表明 :

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.

现在我该如何将它转换为1D数组。因为我想比较两个数组。一个阵列是1D而另一个阵列是2D,这就是为什么我想在1D中使用2D阵列。因此,我需要在1D中轻松比较它们。我正在使用codeigniter。

5 个解决方案

#1

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

您需要遍历数组并将图像存储到一维数组中。

<?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:

#2

Try with -

尝试 -

$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"
}

#3

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

根据php doc,最好的方法是使用array_map:

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()

在将回调函数应用于每个元素之后,array_map()返回一个包含array1的所有元素的数组。回调函数接受的参数数量应与传递给array_map()的数组数量相匹配

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).

回调函数接收迭代数组中的当前元素($ current)($ your_array,2D数组)并返回值以推送到新数组(输出数组是$ output,它是1D数组)。

#4

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

如果php版本是5.5+,请使用array_column()函数

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

对于以下不受支持的版本,请使用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

或使用array_map

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

#5

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

当原始问题“如何比较两个多维数组”可以轻松解决时,为什么要创建一个新问题?

Check out Compare multidimensional arrays in PHP for more input.

查看PHP中的比较多维数组以获取更多输入。

If you really want to convert a multidimensional array into a single dimension, check out this post: How to convert two dimensional array to one dimensional array in php5

如果你真的想将多维数组转换为单个维度,请查看这篇文章:如何在php5中将二维数组转换为一维数组