将一系列PHP变量转换为JSON对象

Question

I have a series of PHP variables:

$a = "a";
$b = "b";
$c = "c";

and so on...

How can I convert all these variables into one single JSON object? Is this possible?

Answer 1

You probably shouldn't have such a structure. That's what arrays are for.

You're currently storing data as sequential strings. This is a bad idea to begin with. When you have data that can be grouped together, it's almost always better to use an array instead. That makes things a whole lot easier.

Now to answer your original question:

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If the number of variables are known, you could simply create an array first and then use json_encode() to create the JSON string:

$arr = array($a, $b, $c);
$json = json_encode($arr);

If the variable names aren't known beforehand, you could use get_defined_vars() to get a list of defined variables.

$arr = array_filter(get_defined_vars(), 'is_string');
echo json_encode($arr);

This is a bad idea though. This would only work if all the variables are to be included in the JSON representation. For example, if you had a private variable $somePrivateData defined in your code, the JSON string will also contain the value of that variable.