它是可能的,在PHP中,在不使用递归或引用的情况下扁平化(bi/multi)维数组?
我只对值感兴趣,所以键可以忽略,我认为在array_map()和array_values()的行。
它是可能的,在PHP中,在不使用递归或引用的情况下扁平化(bi/multi)维数组?
我只对值感兴趣,所以键可以忽略,我认为在array_map()和array_values()的行。
当前回答
<?php
//recursive solution
//test array
$nested_array = [[1,2,[3]],4,[5],[[[6,[7=>[7,8,9,10]]]]]];
/*-----------------------------------------
function call and return result to an array
------------------------------------------*/
$index_count = 1;
$flatered_array = array();
$flatered_array = flat_array($nested_array, $index_count);
/*-----------------------------------------
Print Result
-----------------------------------------*/
echo "<pre>";
print_r($flatered_array);
/*-----------------------------------------
function to flaten an array
-----------------------------------------*/
function flat_array($nested_array, & $index_count, & $flatered_array) {
foreach($nested_array AS $key=>$val) {
if(is_array($val)) {
flat_array($val, $index_count, $flatered_array);
}
else {
$flatered_array[$index_count] = $val;
++$index_count;
}
}
return $flatered_array;
}
?>
其他回答
我只是想指出这是一个折叠,所以可以使用array_reduce
array_reduce($my_array, 'array_merge', array());
编辑:注意,这可以组成平任意数量的水平。我们可以通过以下几种方式做到这一点:
// Reduces one level
$concat = function($x) { return array_reduce($x, 'array_merge', array()); };
// We can compose $concat with itself $n times, then apply it to $x
// This can overflow the stack for large $n
$compose = function($f, $g) {
return function($x) use ($f, $g) { return $f($g($x)); };
};
$identity = function($x) { return $x; };
$flattenA = function($n) use ($compose, $identity, $concat) {
return function($x) use ($compose, $identity, $concat, $n) {
return ($n === 0)? $x
: call_user_func(array_reduce(array_fill(0, $n, $concat),
$compose,
$identity),
$x);
};
};
// We can iteratively apply $concat to $x, $n times
$uncurriedFlip = function($f) {
return function($a, $b) use ($f) {
return $f($b, $a);
};
};
$iterate = function($f) use ($uncurriedFlip) {
return function($n) use ($uncurriedFlip, $f) {
return function($x) use ($uncurriedFlip, $f, $n) {
return ($n === 0)? $x
: array_reduce(array_fill(0, $n, $f),
$uncurriedFlip('call_user_func'),
$x);
}; };
};
$flattenB = $iterate($concat);
// Example usage:
$apply = function($f, $x) {
return $f($x);
};
$curriedFlip = function($f) {
return function($a) use ($f) {
return function($b) use ($f, $a) {
return $f($b, $a);
}; };
};
var_dump(
array_map(
call_user_func($curriedFlip($apply),
array(array(array('A', 'B', 'C'),
array('D')),
array(array(),
array('E')))),
array($flattenA(2), $flattenB(2))));
当然,我们也可以使用循环,但这个问题要求的是一个组合子函数,类似于array_map或array_values。
我需要用HTML输入格式表示PHP多维数组。
$test = [
'a' => [
'b' => [
'c' => ['a', 'b']
]
],
'b' => 'c',
'c' => [
'd' => 'e'
]
];
$flatten = function ($input, $parent = []) use (&$flatten) {
$return = [];
foreach ($input as $k => $v) {
if (is_array($v)) {
$return = array_merge($return, $flatten($v, array_merge($parent, [$k])));
} else {
if ($parent) {
$key = implode('][', $parent) . '][' . $k . ']';
if (substr_count($key, ']') != substr_count($key, '[')) {
$key = preg_replace('/\]/', '', $key, 1);
}
} else {
$key = $k;
}
$return[$key] = $v;
}
}
return $return;
};
die(var_dump( $flatten($test) ));
array(4) {
["a[b][c][0]"]=>
string(1) "a"
["a[b][c][1]"]=>
string(1) "b"
["b"]=>
string(1) "c"
["c[d]"]=>
string(1) "e"
}
您可以使用标准PHP库(SPL)来“隐藏”递归。
$a = array(1,2,array(3,4, array(5,6,7), 8), 9);
$it = new RecursiveIteratorIterator(new RecursiveArrayIterator($a));
foreach($it as $v) {
echo $v, " ";
}
打印
1 2 3 4 5 6 7 8 9
如果你想保留中间键:
function flattenArray(array &$result, $value, string $key = "")
{
if (!is_array($value)) {
$result[$key] = $value;
return $result;
}
foreach ($value as $subKey => $subArray) {
$newKey = $key !== "" ? $key . "_" . $subKey : $subKey;
flattenArray($result, $subArray, $newKey);
}
return $result;
}
$nestedArray = [
"name" => "John",
"pets" => [
["id" => 1, "name" => "snooop"],
["id" => 2, "name" => "medor"],
],
"job" => ["title" => "developper"],
];
$intermediateResult = [];
$flattened = flattenArray($intermediateResult, $nestedArray);
var_dump($flattened);
这将输出:
array(6) {
["name"]=>
string(4) "John"
["pets_0_id"]=>
int(1)
["pets_0_name"]=>
string(6) "snooop"
["pets_1_id"]=>
int(2)
["pets_1_name"]=>
string(5) "medor"
["job_title"]=>
string(10) "developper"
}
看到https://ideone.com/KXLtzZ stdout
二维数组的解
请试试这个:
$array = your array
$result = call_user_func_array('array_merge', $array);
echo "<pre>";
print_r($result);
编辑:8月21日-13日
下面是适用于多维数组的解决方案:
function array_flatten($array) {
$return = array();
foreach ($array as $key => $value) {
if (is_array($value)){
$return = array_merge($return, array_flatten($value));
} else {
$return[$key] = $value;
}
}
return $return;
}
$array = Your array
$result = array_flatten($array);
echo "<pre>";
print_r($result);
裁判:http://php.net/manual/en/function.call-user-func-array.php