数组中的两个索引

Question

我想做这样的事：

<?php
    $times[monday] = ['7-10', '3-5', '1-6'];
    $times[tuesday] = ['5-9', '12-15', '19-22'];
    echo $times[monday][2]
?>

这段代码将回显3-5，因为这是数组$times[monday]中的第二项。

但是，这只是在以下方面出现错误：

Notice: Use of undefined constant monday - assumed 'monday' in /var/www/sch/index.php on line 2

Notice: Use of undefined constant tuesday - assumed 'tuesday' in /var/www/sch/index.php on line 3

Notice: Use of undefined constant monday - assumed 'monday' in /var/www/sch/index.php on line 4

Answer 1

<?php
    $times['monday'] = array('7-10', '3-5', '1-6');
    $times['tuesday'] = array('5-9', '12-15', '19-22');
    echo $times['monday'][2]
?>

您将需要引用数组字符串元素标识符(例如，“周一”)，并使数组多维，如图所示。

如果没有引号，字符串monday将作为常量处理。

请注意，代码：

echo $times['monday'][2]

会回显1-6，因为数组基于0(元素从0开始)。如果您想要3-5，它将是：

echo $times['monday'][1]

Answer 2

您忘记了引号，要初始化数组，应该在括号前添加array关键字：

<?php
    $times['monday'] = array('7-10', '3-5', '1-6');
    $times['tuesday'] = array('5-9', '12-15', '19-22');
    echo $times['monday'][2];
?>