从一个多维阵列创建一个下拉列表 [英] Create a dropdown list from a multi-dimensional array

问题描述

我得到这个数组：

Array
(
    [0] => Array
        (
            [id] => 1
            [name] => tomato
        )

    [1] => Array
        (
            [id] => 2
            [name] => carrot
        )

    [2] => Array
        (
            [id] => 3
            [name] => apple
        )

)

我要打印的每个键/值对在HTML表单，像这样：

I want to print each key/value pair in an HTML form, like so:

<select>
    <option value="1">tomato</option>
    <option value="2">carrot</option>
    <option value="3">apple</option>
</select>

所以，我使用foreach循环遍历数组外的三个项目，然后尝试打印在一行内数组中的项目。我被困在最后一位。到目前为止，我所得到的最接近是这样的：

So, I'm using a foreach loop to iterate over the three items in the outer array and then try to print the items in the inner array on a single line. I'm stuck with the last bit. The closest I've got so far is this:

foreach ($food_opts as $key => $value) {
    foreach ($value as $k => $v) {
        echo '<pre>' . $v . '</pre>';
    }
}

本检索我需要的数据，但不是在一个可用的格式为：

This retrieves the data I need but not in a usable format:

1
tomato
2
carrot
3
apple

总之，你如何针对内部阵列中的各个项目？是这样的：

In short, how do you target individual items in an inner array? Something like:

foreach ($food_opts as $key => $value) {
    foreach ($value as $k => $v) {
        echo '<pre>' . $v[0] . ' - ' . $v[1] . '</pre>';
    }
}

我明白为什么上面code不工作，但无法弄清楚如何获得数据我怎么想的那样。

I understand why the above code doesn't work but can't figure out how to get the data how I want it.

推荐答案

您不需要嵌套的foreach 在这里。只要做到：

You don't need a nested foreach here. Just do:

foreach ($food_opts as $key => $arr) {
    echo '<option value="'.$arr['id'].'">'.$arr['name'].'</option>', PHP_EOL;
}

或者，您可以使用 的printf（） 为一个更简洁的方法：

Or, you can use printf() for a more cleaner approach:

foreach ($food_opts as $key => $arr) {
    printf('<option value="%s">%s</option>', $arr['id'], $arr['name']).PHP_EOL;
}

的的printf（）家庭功能用途％字符作为占位符。 ％S 的意思是把下一个参数并打印它作为一个字符串。同样，％d个的意思是把下一个参数，并打印成int类型。

The printf() family of functions uses % character as a placeholder. %s means "take the next argument and print it as a string". Similarly, %d means "take the next argument and print it as an int".

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