由于某种原因,我的代码前一分钟是数组,下一分钟不是。我只是在学习php,我搞不懂。我用这个页面解决了大部分问题:如何在一个页面上添加两个谷歌图表?
我的代码也用于将数据显示为表的页面。在那一页上,它运行得很好。。。。但由于某种原因,我在饼图页面上得到了为foreach()提供的无效参数。。。它说它不是一个数组。我不知道该怎么解决这个问题。
我使用的网址是?action=分数&data=pie,所以它应该在"get_universities()"中列出所有的大学(那里有3所)。
有人能帮忙吗?
交换机:
// Showing scores
case 'scores':
// Grab the Uni ID and use the appropriate query
if (isset($_GET['uni_id']))
{
$uni_id = $_GET['uni_id'];
$uni = get_university($uni_id);
}
else
{
$uni = get_universities();
}
// We have to display this data according to the request
if (isset($_GET['data']))
{
$data = $_GET['data'];
}
else
{
$data = "table";
}
// Display the data accordingly
include (root . '/view/' . $data . '_view.php');
break;
饼图:
// Create the data table.
<?php foreach ($uni as $uni) : ?>
var data<?php echo $uni['university_id']; ?> = new google.visualization.DataTable();
data<?php echo $uni['university_id']; ?>.addColumn('string', 'Area');
data<?php echo $uni['university_id']; ?>.addColumn('number', 'Score');
data<?php echo $uni['university_id']; ?>.addRows([
['Teaching', <?php echo $uni['teaching_score']; ?>],
['Intl Outlook', <?php echo $uni['int_outlook_score']; ?>],
['Industry Income', <?php echo $uni['ind_income_score']; ?>],
['Research', <?php echo $uni['research_score']; ?>],
['Citations', <?php echo $uni['citations_score']; ?>]
]);
<?php endforeach ?>
// Set chart options
<?php foreach ($uni as $uni) : ?>
var options<?php echo $uni['university_id']; ?> = {'title':'<?php echo $uni['university_name']; ?> Scores',
'width':400,
'height':300};
<?php endforeach ?>
// Instantiate and draw our chart, passing in some options.
<?php foreach ($uni as $uni) : ?>
var chart<?php echo $uni['university_id']; ?> = new google.visualization.PieChart(document.getElementById('chart_div<?php echo $uni['university_id']; ?>'));
chart.draw(data<?php echo $uni['university_id']; ?>, options<?php echo $uni['university_id']; ?>);
<?php endforeach ?>
表格视图(有效):
<?php foreach ($uni as $uni) : ?>
<td>
<a href="?uni=<?php echo $uni['university_id']; ?>">
<?php echo $uni['university_name']; ?>
</a>
</td>
<etc>
问题出在foreach
语句上:
foreach ($uni as $uni) :
在这里,您可以覆盖$uni
变量。对集合和项目使用不同的名称,例如:
foreach ($uni as $theUni) :
// also change instances of $uni below
编辑
以上是错误的。foreach
的第一个参数的解析只发生过一次,所以在中foreach
不会有问题。然而,foreach
并不是一个新的作用域,因此如果您计划重用数组变量,则需要选择一个不同的名称作为迭代器,这样它就不会被重写。
$a = array(); // $a is array
foreach ($a as $a) {
// $a is element of original $a
}
// $a is the last element of the original $a array
foreach ($a as $a) // Fail, since $a is not an array anymore