打印带递增键的多维数组答案

【问题标题】：Print Multidimensional array with incrementing key打印带递增键的多维数组
【发布时间】：2018-03-30 06:15:45
【问题描述】：

我有两个数组第一个是学生姓名，第二个是他最喜欢的作者选择如下

$student 数组如下

 array (size=3)
      0 => string 'Jane' (length=4)
      1 => string 'Michelle' (length=8)
      2 => string 'Mark' (length=4)

现在第二个数组Author $selection如下：

array (size=3)
  0 => 
    array (size=3)
      0 => string 'Mark Twaine' (length=11)
      1 => string 'E A Poe' (length=7)
      2 => string 'James Joyce' (length=11)
  1 => 
    array (size=3)
      0 => string 'Oscar' (length=11)
      1 => string 'Leo Toby' (length=7)
      2 => string 'James Joyce' (length=11)
  2 => 
    array (size=3)
      0 => string 'Leo Toby' (length=11)
      1 => string 'E A Poe' (length=7)
      2 => string 'James Joyce' (length=11)

现在我想显示学生姓名和他最喜欢的作者，即 Jane 最喜欢的作者是 Mark Twaine、E A Poe、James Joyce 和 Michelle 最喜欢的作者是 Oscar、Leo Toby、James Joyce 和 Mark 最喜欢的作者是 Leo Toby、E A坡，詹姆斯·乔伊斯 ...

到目前为止我已经尝试过了

foreach( $student as $key => $val  ) {
    echo $val." read ";
    foreach( $selection as $key1 ) {
        foreach ($key1 as $key2 => $val2){

        echo $val2;
        echo ' and ';
    } 
       echo "<br/>"; 
}

并将其作为输出

Jane favorite is Mark Twaine and E A Poe and James Joyce and 
Oscar and Leo Toby and James Joyce and 
Leo Toby and E A Poe and James Joyce and 
Michelle favorite is Mark Twaine and E A Poe and James Joyce and 
Oscar and Leo Toby and James Joyce and 
Leo Toby and E A Poe and James Joyce and  
Mark favorite is Mark Twaine and E A Poe and James Joyce and 
Oscar and Leo Toby and James Joyce and 
Leo Toby and E A Poe and James Joyce and

代替

    Jane favorite is Mark Twaine and E A Poe and James Joyce
    Michelle favorite is Oscar and Leo Toby  and James Joyce
    Mark favorite is Leo Toby and E A Poe and James Joyce

我希望 foreach 循环限制为只有一个带有递增键的数组值

【问题讨论】：

标签： php multidimensional-array

【解决方案1】：

您可以使用array_combine() 将学生和选择结合起来。然后，使用implode() 回应每个学生的选择：

$student = ['Jane','Michelle','Mark'];
$selection = [
  ['Mark Twaine', 'E A Poe', 'James Joyce'],
  ['Oscar', 'Leo Toby', 'James Joyce'],
  ['Leo Toby', 'E A Poe', 'James Joyce'],
];

$comb = array_combine($student, $selection);

foreach ($comb as $student => $item) {
  echo $student . ' favorite is '. implode(' and ', $item). '<br>' ;
}

输出：

Jane favorite is Mark Twaine and E A Poe and James Joyce
Michelle favorite is Oscar and Leo Toby and James Joyce
Mark favorite is Leo Toby and E A Poe and James Joyce

【讨论】：

【解决方案2】：

问题是您的第二个foreach() (foreach( $selection as $key1 ) {) 正在循环遍历每个学生的所有选择。此时，您只需为对应的学生挑选出所选内容（将 $student 数组的键与 $selection 数组的键匹配）。

$student = ['Jane', 'Michelle', 'Mark'];
$selection = [['Mark Twaine','E A Poe','James Joyce'],
    ['Oscar','Leo Toby','James Joyce'],
    ['Leo Toby','E A Poe','James Joyce']];

foreach( $student as $key => $val  ) {
    echo $val." read ";
    foreach( $selection[$key] as $val2 ) {
            echo $val2;
            echo ' and ';
    }
    echo "<br/>";
}

您可以看到内部foreach 使用第一个数组中的$key 来挑选要循环的选择。

您可以使用implode() 缩短内部循环，这也消除了输出中多余的“和”。

foreach( $student as $key => $val  ) {
    echo $val." read ".implode(' and ', $selection[$key])."<br/>";
}

【讨论】：