foreach: “in” v. “as”

Question

What is the difference between these two usages of foreach?

foreach ($nodes as $node) {
 //do stuff
}

foreach ($odp in $ftw) {
  //do more stuff
}

Answer 1

第一个是合法的PHP，第二个不是 。

Answer 2

Using in in PHP doesn't work. In Javascript however, a similar form is acceptable and they differ thusly:

var obj = {
    'a' : 'Apple',
    'b' : 'Banana',
    'c' : 'Carrot'
};

for (var i in obj) {
    alert(i); // "a", "b", "c"
}

for each (var i in obj) {
    alert(i); // "Apple", "Banana", "Carrot"
}

basically, for each ... in ... (Javascript) or foreach ... as ... (PHP) will give the value of the properties of the object, whereas for ... in ... (javascript) will give you the name of each property.