Confusing array sorting in PHP

What's the best way to sort this array alphabetically, by String1? The key numbering should always be numerical still.

Before:

Key     | String1    Int1 String2 Int2
--------------------------------------
0       | Alligator  3    Cake    7
1       | Crocodile  17   foobar  9
2       | Bear       1    test    6
3       | Aardvark   2    lolwhat 3

After:

Key     | String1    Int1 String2 Int2
--------------------------------------
0       | Aardvark   2    lolwhat 3
1       | Alligator  3    Cake    7
2       | Bear       1    test    6
3       | Crocodile  17   foobar开发者_如何学编程  9     

Essentially, I have an array which has a bunch of arrays in it, how can I sort those arrays within the first array alphabetically using a particular element?

---

You probably want usort which lets you define a comparator callback function.

http://www.php.net/manual/en/function.usort.php

---

You will want a compare function like the following:

function compare($a, $b)
{
    if ($a['String1'] < $b['String1'])
        return -1;
    if ($a['String1'] > $b['String1'])
        return 1; 

    // At this point the strings are identical and you can go into 
    // a second value to compare something else if you wish 
    if ($a['String2'] < $b['String2'])
        return -1;
    if ($a['String2'] > $b['String2'])
        return 1;

    // as long as you cover the three situations you are fine. 
    return 0
}

---

function str1cmp($a, $b) {
    return strcmp($a['string1'], $b['string1']);
}

usort($array, 'str1cmp');