在foreach循环中使用PHP常量

Question

I need to use PHP contants in foreach loop:

define('WEBS', 'http://google.com, http://yahoo.com');
foreach (WEBS as $a) {
    //do something
}

However I managed to do that by following code, although it works fine but aptana editor shows syntax error. Please guide me how to do that in the correct manner.

foreach (get_defined_constants(true)['user']['WEBS'] as $w) {
//do something
} 

Answer 1

You have to explode the values first

foreach (explode(', ', WEBS) as $url) { ...

explode() will break a string into an array so that you can iterate through it

---

Alternatively, you could even use preg_split.

foreach(preg_split('/,\s*/', WEBS) as $url) { ...

preg_split() allows you to split your string based on a regular expression. It returns an array. As an example, using this regex, the space following the comma is optional.

# a string like this
foo.com, hello.com,world.com,  test.com

# would still split properly to
[
  'foo.com',
  'hello.com',
  'world.com',
  'test.com'
]

Regex methods are not always necessary. But I thought I'd show you that a little more control is available when it's necessary.

---

Aptana is showing you an error because you can't use [] after a func() prior to PHP 5.4. To get around that, you can do things like:

$constants = get_defined_constants(true);
$constants['user']['WEBS'];

But in this case WEBS should be just fine. The only issue you were having is that you needed to convert the string to an array first.