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[英]Group subarray data by one column and form comma-separated values from the secondary value in each group
[英]Group subarrays by one column, make comma-separated values from other column within groups
我有一个看起来像这样的数组:
$array = [
["444", "0081"],
["449", "0081"],
["451", "0081"],
["455", "2100"],
["469", "2100"]
];
我需要分组为一个新的数组,如下所示:
array (
0 =>
array (
0 => '444,449,451',
1 => '0081',
),
1 =>
array (
0 => '455,469',
1 => '2100',
),
)
我尝试了许多脚本,但没有成功。
function _group_by($array, $key) {
$return = array();
foreach($array as $val) {
$return[$val[$key]][] = $val;
}
return $return;
}
$newArray = _group_by($array, 1); // (NO SUCCESS)
应该有更优雅的解决方案,但是我能想到的最简单的解决方案就是这个。
// The data you have pasted in the question
$data = [];
$groups = [];
// Go through the entire array $data
foreach($data as $item){
// If the key doesn't exist in the new array yet, add it
if(!array_key_exists($item[1], $groups)){
$groups[$item[1]] = [];
}
// Add the value to the array
$groups[$item[1]][] = $item[0];
}
// Create an array for the data with the structure you requested
$structured = [];
foreach($groups as $group => $values){
// With the array built in the last loop, implode it with a comma
// Also add the 'key' from the last array to it ($group)
$structured[] = [implode(',', $values), $group];
}
我还没有测试过,但是类似的方法应该可以解决。 这简单地遍历给定的数组并以结构化的方式收集所有条目(因此$groups
变量将为共享密钥的每个组包含一个数组条目,并且该键将对应于给定数组中每个项目的第二个项目)。 从那里开始,仅是对其进行重组以获取所需的格式。
编写两个循环对于此任务来说太费力了。 使用isset()
并在迭代时将临时键应用于输出数组。 完成数据分组后,使用array_values()
重新索引输出。
代码( 演示 )
$array = [
["444", "0081"],
["449", "0081"],
["451", "0081"],
["455", "2100"],
["469", "2100"]
];
foreach ($array as $row) {
if (!isset($result[$row[1]])) {
$result[$row[1]] = $row; // first occurrence of group, save whole row
} else {
$result[$row[1]][0] .= ',' . $row[0]; // not first occurrence, concat first element in group
}
}
var_export(array_values($result));
输出:
array (
0 =>
array (
0 => '444,449,451',
1 => '0081',
),
1 =>
array (
0 => '455,469',
1 => '2100',
),
)
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