我需要在php中使用json的foreach循环，但我只想返回唯一的值

Question

我已经将json解析并解码为php文件。json的格式类似如下:

{"name":"John Doe", "records":[{"sample": "sample","fields":{"date":"Sample Date","Sample Field":"Sample value", "id": "sampleid"}}

我在那个文件中有很多类似的记录。我一直使用foreach循环来返回所有的date字段。循环看起来像这样:

$records = $records_json['records'];
foreach($records as $record) {
        echo "<option>" . $record['fields']['date'] . "</option>";
}

现在，它返回所有的日期。然而，有很多重复的日期，我只想返回唯一的日期(没有重复的)。有办法做到这一点吗?

Answer 1

您可以使用存储日期的数组，并根据该数组中的值检查新日期，以查看是否有"new"日期，如果没有，则为唯一日期，应添加到数组中。

$records = $records_json['records'];
$uniques = array():
foreach($records as $record) {
    if (!in_array($record['fields']['date'], $uniques)) {
        $uniques[] = $record['fields']['date'];
    }
}
foreach ($uniques as $unique) {
    echo "<option>" . $unique . "</option>";
}

Answer 2

试试下面的代码:

<?php
$records_json = '{"name":"John Doe", "records":[{"sample": "sample","fields":{"date":"Sample Date","Sample Field":"Sample value", "id": "sampleid"}}]}';
$arr = json_decode($records_json,TRUE);
$records = $arr['records'];
foreach($records as $record) {
        echo  $record['fields']['date'] ;
}
?>

Answer 3

在线演示

 <?php
$json = '{"name":"John Doe", "records":[{"sample": "sample","fields":{"date":"Sample Date","Sample Field":"Sample value", "id": "sampleid"}}]}';
$json  = json_decode($json , true);
$dates = [];
foreach($json['records'] as $record) {
   $date = $record['fields']['date'];
   if(!isset($dates[$date]))
      $dates[]= $date;
}
var_dump($dates);

Answer 4

您可以创建一个日期数组，然后使用array_unique进行筛选。

<?php
$array  = ['foo', 'foo', 'bar', 'baz'];
$unique = array_unique($array);
var_export($unique);

输出:

array (
  0 => 'foo',
  2 => 'bar',
  3 => 'baz',
)