[SOLVED] a little 'foreach' problem

[Heylance]

yup! it's official, not quite getting it. a little help please!!!

 

I'm trying (again) to sort an array by the strlen of the values.

This is a solution I got here before, but have run into a snag.

 

$my_cars = array('chevy', 'chevys', 'dodge', 'dodges', 'lancer', 'mitsubishi', 'nissan');

if($my_cars){
   foreach($my_cars as $key => $val){
     $car = strlen($val);
     $car_list[$car] = $val;
  }
}

echo "<pre>\n";
print_r($car_list);
echo "</pre>\n";

Array
(
    [5] => dodge
    [6] => nissan
    [10] => mitsubishi
)

ksort($car_list);
$car_list = array_reverse($car_list);

echo "<pre>\n";
print_r($car_list);
echo "</pre>\n";

Array
(
    [0] => mitsubishi
    [1] => nissan
    [2] => dodge
)

 

Where did chevys, dodges and lancer go?? They got lost back in the foreach section.

 

As you can see, I am trying to recreate the array and using the strlen to sort on. I was given this solution a few weeks ago. It seems that if any of the values are the same strlen, only the last one in the array is kept. What to do?

 

Any suggestions.... Is it possible to do???

[Psycho]

Yes, it is possible. The problem is that you are using the string length as the array index. Since 'chevys' and 'lancer' have the same string length the index of [6] first gets defined as 'chevys', then it gets redefined as 'lancers'.

 

Here's one solution:

 

<?php

function sortByLength($a, $b) {
    if (strlen($a)==strlen($b)) {
        //If length =, sort by alpha
        return strcmp($a, $b);
    }
    return (strlen($a)>strlen($b)) ? 1 : -1; 
}

$my_cars = array('chevy', 'chevys', 'dodge', 'dodges', 'lancer', 'mitsubishi', 'nissan');

if($my_cars){
  usort($my_cars, "sortByLength");
}

echo "<pre>\n";
print_r($my_cars);
echo "</pre>\n";

?>

[Psycho]

Here's another approach

<?php

$my_cars = array('chevy', 'chevys', 'dodge', 'dodges', 'lancer', 'mitsubishi', 'nissan');

if($my_cars){
   foreach($my_cars as $key => $val){
     $tmp_list[$val] = strlen($val);
  }
  asort($tmp_list);
  $my_cars = array_keys($tmp_list);
}

echo "<pre>\n";
print_r($my_cars);
echo "</pre>\n";

?>

[Heylance]

Thanks mjdamato,

 

Bingo, you made it look too easy!

Your second solution was the easiest for me to get a grip on. I threw a little arsort it and Baaammm!

Just what the doctor ordered.

Thanks so much!!!!

 

On the first one, I will have to study a little, which is good..

One question

On the line:

  return (strlen($a)>strlen($b)) ? 1 : -1;

 

What is the ? for?

Remember I'm still a neeewwwbie.

 

[Psycho]

That is a shorthand version of an If/Else statement. I believe the correct name is the ternarry operator. Basically, that line states is the length of A is greater than the length of B return 1, else return -1.

 

Here is a short article on it: http://php.codenewbie.com/articles/php/1480/The_Ternary_Operator-Page_1.html

 

 

Personally, I woudl think the first example is more efficient, but I have not tested that hypothesis.