你能在PHP中获得一个变量名作为字符串吗？ （你应该吗？）

Question

Say you have several large arrays of variables (which generally are strings), and you want to change how they are displayed on certain pages – for example by concatenating each of them with $prefix and $suffix:

$arr = array($foo, $bar, $baz)

$foo_display = $prefix . $foo . $suffix
$bar_display = $prefix . $bar . $suffix
$baz_display = $prefix . $baz . $suffix

How would you avoid having to make all these assignments manually? I originally assumed there would be some function which would return a variable's name as a string (call it "varname()"), in which case the code might look like this:

foreach ($arr as &$value) {
    ${varname($value)."_display"} = $prefix . $value . $suffix
}

But I haven't been able to find such a function, and people in this similar thread seemed to think the entire concept was suspect.

PS: I'm new to programming, sorry if this is a dumb question :)

Answer 1

There are multiple problems with what you want to do. For example, the name of the variable is not accessible. The code $arr = array($foo, $bar, $baz) creates an array with the values of the $foo, etc. If you then changed the value of $foo, the value of $arr[0] is still the old value of $foo, so it's not even clear what it would mean to have access to the variables name.

Even if it were easy to do, I would consider it very poor practise, simply because you'd need to know by introspection what the correct variable names would be.

Of course, this is all easily solved if you had an associative array. For example:

$arr = array('Foo' => $foo, 'Bar' => $bar, 'Baz' => $baz)

This could easily be altered to produce what you want. For example:

$display = array();
foreach($arr as $key => $value) 
   $display[$key] = $prefix . $value . $suffix;