Question

我有以下代码可以使用：

$apple_color = "red";
$pear_color = "green";
$banana_color = "yellow";
$grape_color = "purple";

foreach(array("apple","pear","banana","grape") as $idx=>$fname) {
    $var = "${fname}_color";
    echo "$var = ${$var}<br>".PHP_EOL;
}

但是，我无法弄清楚如何通过消除$ var变量来缩短代码：

foreach(array("apple","pear","banana","grape") as $idx=>$fname) {
    echo "${fname}_color = ${${fname}_color}<br>".PHP_EOL;
}

＆＃34; $ {$ {fname} _color＆＃34;返回一个PHP错误，指出＆＃34;语法错误，意外＆＃39; _color＆＃39; （T_STRING）＆＃34;

PHP小提琴：http://phpfiddle.org/lite/code/wrfp-yqkx

Answer 1

这个怎么样？使用${'string'}构建

foreach(["apple","pear","banana","grape"] as $fname) {
    echo "{$fname}_color = ".${$fname.'_color'}."<br>".PHP_EOL;
}

Answer 2

不是为每种颜色设置单独的变量，而是将颜色存储在由水果名称索引的数组中。这样就可以避免使用变量变量。

$colors = [
    'apple' => 'red',
    'pear' => 'green',
    'banana' => 'yellow',
    'grape' => 'purple'
];

foreach (["apple","pear","banana","grape"] as $fname) {
    echo "{$fname}_color = $colors[$fname]<br>".PHP_EOL;
}

Answer 3

使用字符串格式来简化您的生活：

echo sprintf('$%s_color = %s<br>' . PHP_EOL, $fname, ${$fname . '_color'});

设置PHP嵌套变量

3 个答案: