我有一个如下所示的数组，我想要做的是，创建基于datepart的多个数组，如（2011-02-04）：
Array
(
[0] => Array
(
[avgvalue] => 0
[maxvalue] => 0
[minvalue] => 0
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-04T11:00:00.000Z
)
[1] => Array
(
[avgvalue] => 268.3
[maxvalue] => 268.3
[minvalue] => 268.3
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-04T12:00:00.000Z
)
[2] => Array
(
[avgvalue] => 268.391666667
[maxvalue] => 268.4
[minvalue] => 268.3
[nrsamples] => 0.0288675134595
[stddeviation] => 0.0288675134595
[timestamp] => 2011-02-04T13:00:00.000Z
)
[3] => Array
(
[avgvalue] => 268.433333333
[maxvalue] => 268.5
[minvalue] => 268.4
[nrsamples] => 0.0492365963918
[stddeviation] => 0.0492365963918
[timestamp] => 2011-02-04T14:00:00.000Z
)
[4] => Array
(
[avgvalue] => 268.5
[maxvalue] => 268.5
[minvalue] => 268.5
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-04T15:00:00.000Z
)
[5] => Array
(
[avgvalue] => 268.575
[maxvalue] => 268.6
[minvalue] => 268.5
[nrsamples] => 0.0452267016867
[stddeviation] => 0.0452267016867
[timestamp] => 2011-02-04T16:00:00.000Z
)
[6] => Array
(
[avgvalue] => 268.616666667
[maxvalue] => 268.7
[minvalue] => 268.6
[nrsamples] => 0.0389249472081
[stddeviation] => 0.0389249472081
[timestamp] => 2011-02-04T17:00:00.000Z
)
[7] => Array
(
[avgvalue] => 268.7
[maxvalue] => 268.7
[minvalue] => 268.7
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-04T18:00:00.000Z
)
[8] => Array
(
[avgvalue] => 268.741666667
[maxvalue] => 268.8
[minvalue] => 268.7
[nrsamples] => 0.0514928650545
[stddeviation] => 0.0514928650545
[timestamp] => 2011-02-04T19:00:00.000Z
)
[9] => Array
(
[avgvalue] => 268.8
[maxvalue] => 268.8
[minvalue] => 268.8
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-04T20:00:00.000Z
)
[10] => Array
(
[avgvalue] => 268.883333333
[maxvalue] => 268.9
[minvalue] => 268.8
[nrsamples] => 0.0389249472081
[stddeviation] => 0.0389249472081
[timestamp] => 2011-02-04T21:00:00.000Z
)
[11] => Array
(
[avgvalue] => 268.908333333
[maxvalue] => 269
[minvalue] => 268.9
[nrsamples] => 0.0288675134595
[stddeviation] => 0.0288675134595
[timestamp] => 2011-02-04T22:00:00.000Z
)
[12] => Array
(
[avgvalue] => 269
[maxvalue] => 269
[minvalue] => 269
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-04T23:00:00.000Z
)
[13] => Array
(
[avgvalue] => 269.05
[maxvalue] => 269.1
[minvalue] => 269
[nrsamples] => 0.0522232967867
[stddeviation] => 0.0522232967867
[timestamp] => 2011-02-05T00:00:00.000Z
)
[14] => Array
(
[avgvalue] => 269.1
[maxvalue] => 269.1
[minvalue] => 269.1
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-05T01:00:00.000Z
)
[15] => Array
(
[avgvalue] => 269.166666667
[maxvalue] => 269.2
[minvalue] => 269.1
[nrsamples] => 0.0492365963917
[stddeviation] => 0.0492365963917
[timestamp] => 2011-02-05T02:00:00.000Z
)
[16] => Array
(
[avgvalue] => 269.2
[maxvalue] => 269.2
[minvalue] => 269.2
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-05T03:00:00.000Z
)
[17] => Array
(
[avgvalue] => 269.291666667
[maxvalue] => 269.3
[minvalue] => 269.2
[nrsamples] => 0.0288675134595
[stddeviation] => 0.0288675134595
[timestamp] => 2011-02-05T04:00:00.000Z
)
[18] => Array
(
[avgvalue] => 269.333333333
[maxvalue] => 269.4
[minvalue] => 269.3
[nrsamples] => 0.0492365963917
[stddeviation] => 0.0492365963917
[timestamp] => 2011-02-05T05:00:00.000Z
)
[19] => Array
(
[avgvalue] => 269.4
[maxvalue] => 269.4
[minvalue] => 269.4
[nrsamples] => 0
[stddeviation] => 0
[timestamp] => 2011-02-05T06:00:00.000Z
)
)
以上列表是数组。它有时间戳键，我爆炸了时间戳键，以便我得到日期和时间部分分离，现在我有问题将数组拆分成子数组。我想要的是2011-02-04有一个数组（包含该日期的所有值）和2011-02-05的另一个数组（包含所有那个日期的值）。这可以是动态的，我的意思是日期可以更多。那么，我该怎么办呢。
我想要它：
array[0] => array(... list of all the values for 2011-02-04),
array[1] => array(...list of all values for 2011-02-05)
被困在这里，无法使其发挥作用。请建议。
答案 0 :(得分：7)
假设所有条目（看起来都是）的日期格式相同，您可以简单地循环遍历数组：
$result = array();
foreach($array as $item) {
$date = strstr($item['timestamp'], 'T', true);
if(!array_key_exists($date, $result)) {
$result[$date] = array();
}
$result[$date][] = $item;
}
根据原始数组中项目的顺序，您可能必须使用ksort按时间顺序对$result数组进行排序。
答案 1 :(得分：0)
在推送新的子数组之前，无需检查数组键是否存在。只需将子数组推入带有日期键的子数组即可。
解决方案很简单：（Demo）
$result = [];
foreach ($array as $row) {
$result[substr($row['timestamp'], 0, 10)][] = $row;
}
分组后，如果要对组进行排序，请对ASC使用ksort($result)或对DESC使用krsort($result)。如果要重新索引第一级键，请使用$result = array_values($result)。