用php在多维数组中搜索和打印输出

我正在学习PHP中的数组。我正在研究多维数组，其中我面临一个问题

以下是示例多维数组的图示：

Array
(
    [0] => Array
        (
            [venue] => chicago
            [course] => science
            [time] => 2pm
        )
    [1] => Array
        (
             [venue] => New York
             [course] => Robotics
             [time] => 3 p.m.
        )
    [2] => Array
        (
             [venue] => New York
             [course] => Science
             [time] => 4 p.m.
        )
    [3] => Array
        (
             [venue] => Chicago
             [course] => Robotics
             [time] => 4 p.m.
        )
)

我希望从上述阵列打印的所需输出为：

Chicago
Science  2 p.m.
Robotics  4 p.m. 

New York 
Science 4 p.m.
Robotics 3 p.m. 

---

有谁能指导我如何解决这个问题吗？

您可以使用foreach获得以下结果

foreach ($rows as $row) {
    echo $row['venue']."<br>";
    echo $row['firstname']."  ".$row['lastname'];
}

foreach（$rows作为$row）{
echo$row['vention']。“
”；
echo$row['firstname']。“”.$row['lastname']；
}

您可以使用foreach获得以下结果

foreach ($rows as $row) {
    echo $row['venue']."<br>";
    echo $row['firstname']."  ".$row['lastname'];
}

foreach（$rows作为$row）{
echo$row['vention']。“
”；
echo$row['firstname']。“”.$row['lastname']；
}

为每个场馆创建一个新阵列，并将课程和时间分别存储为键和值

// define an array
$new_array = array();
// loop the array
foreach($array as $key=>$value){
    // create an array with each venue and  course and time as key and values
    $new_array[$value['venue']][$value['course']] = $value['time'];
}

循环新数组并根据需要显示结果

// loop the new array
foreach($new_array as $key=>$value){
    echo $key."\n";  // echo the venue
    krsort($value);  // Sort an array by key in reverse order
    foreach($value as $k=>$v){
        echo $k . ' ' . $v."\n"; // echo the course and time
    }
    echo "\n";
}

发出

chicago
science 2pm
robtics 4pm

newyork
science 4pm
robotics 3pm

---

为每个场地创建一个新数组，并将课程和时间分别存储为键和值

// define an array
$new_array = array();
// loop the array
foreach($array as $key=>$value){
    // create an array with each venue and  course and time as key and values
    $new_array[$value['venue']][$value['course']] = $value['time'];
}

循环新数组并根据需要显示结果

// loop the new array
foreach($new_array as $key=>$value){
    echo $key."\n";  // echo the venue
    krsort($value);  // Sort an array by key in reverse order
    foreach($value as $k=>$v){
        echo $k . ' ' . $v."\n"; // echo the course and time
    }
    echo "\n";
}

发出

chicago
science 2pm
robtics 4pm

newyork
science 4pm
robotics 3pm

---

一种方法是首先按地点对阵列进行排序

usort

可用于此

usort($events, function($a, $b) {
    return strcmp($a['venue'], $b['venue']);
});

数组排序后，您可以对其进行迭代，并在每次到达新地点时输出一个标题

$previousVenue = null;
foreach ($events as $event) {

    // check if this venue is the same as the previous, output header if not
    if ($event['venue'] != $previousVenue) {
        echo "<h3>$event[venue]</h3>";
    }
    // always output course and time
    echo "$event[course] $event[time]<br>";

    // current venue becomes previous venue
    $previousVenue = $event['venue'];
}

$previousvention=null；
foreach（$events作为$event）{
//检查此地点是否与前一地点相同，如果不相同，则输出标题
如果（$event['vention']！=$previousvention）{
回声“$事件[地点]”；
}
//始终输出课程和时间
回显“$event[课程]$event[时间]
”；
//当前场地变为上一个场地
$PreviousVincement=$event['Vincement']；
}

一种方法是首先按地点对阵列进行排序

usort

可用于此

usort($events, function($a, $b) {
    return strcmp($a['venue'], $b['venue']);
});

数组排序后，您可以对其进行迭代，并在每次到达新地点时输出一个标题

$previousVenue = null;
foreach ($events as $event) {

    // check if this venue is the same as the previous, output header if not
    if ($event['venue'] != $previousVenue) {
        echo "<h3>$event[venue]</h3>";
    }
    // always output course and time
    echo "$event[course] $event[time]<br>";

    // current venue becomes previous venue
    $previousVenue = $event['venue'];
}

$previousvention=null；
foreach（$events作为$event）{
//检查此地点是否与前一地点相同，如果不相同，则输出标题
如果（$event['vention']！=$previousvention）{
回声“$事件[地点]”；
}
//始终输出课程和时间
回显“$event[课程]$event[时间]
”；
//当前场地变为上一个场地
$PreviousVincement=$event['Vincement']；
}