[RESOLVED] sort list alphabetically

zzz

I've got an array of country ISO codes

$countries = array("AU","CA","CO","DE","DK","ES","GB","GR","IL","IN","IT","NO","PA","US","ZA");

Now I'm building a list via a loop:

foreach ($countries as $key => $value) {
 echo $value.'<br>';
}

The results I get look fine

AU
CA
CO
DE
DK
ES
GB
etc.

Now I'd like to use another array to replace ISO codes with full country names.

$iso2name = array("AU" => "AUSTRALIA", "CA" => "CANADA", ... "DK" => "DENMARK");

by doing

foreach ($countriesas $key => $value) {
 echo $iso2name[$value].'<br>';
}

However, now my output looks out of order

Australia
Canada
Colombia
Germany
Denmark
Spain
United Kingdom
Greece
Israel
India
Italy
Norway
Panama
United States
South Africa

Is there any way the final list could be sorted alphabetically? If yes, how?

😕

coldwerturkey

look into sort()

zzz

I can sort $countries but not $iso2name[$value]... Actually since the innitial post i turned the list into a drop down and the problem is still there:

	echo '<select>';

foreach ($countries as $key => $value) {
	echo '<option value="'.$value.'"'>'.$iso2name[$value];
}
echo '</select>';

cahva

Use asort:

asort($countries);
foreach ...

zzz

this will sort ISO codes

$countries = array("AU","CA","CO","DE","DK","ES","GB","GR","IL","IN","IT","NO","PA","US","ZA");

I actually need to sort full names

$iso2name = array("AU" => "AUSTRALIA", "CA" => "CANADA", ... "DK" => "DENMARK");

I think I need to create some sort of weird array out of the two I have and then run a loop...

cahva

Well thats what asort does. Sort them alphabetically by array's values maintaining index association.

$arr = array('FI' => 'FINLAND', 'SE' => 'SWEDEN', 'RU' => 'RUSSIA');
print_r($arr);

asort($arr);

print_r($arr);

Will print:

Array
(
    [FI] => FINLAND
    [SE] => SWEDEN
    [RU] => RUSSIA
)
Array
(
    [FI] => FINLAND
    [RU] => RUSSIA
    [SE] => SWEDEN
)

Why not just use the $iso2name and forget about the $countries.

foreach ($iso2name as $iso => $name) {
        echo '<option value="'.$iso.'">'.$name.'</option>';
}

I think you are making simple thing complex 🙂

zzz

Because $countries only contains the list of countries that I can use. Is there a way, perhaps, I loop the $iso2name but only show values that exist in $countries? Perhaps I can rebuild a new array using some sort of array difference function? Hmm, I think I'm onto something here...

I think I should b able to use

array_intersect($iso2name, $countries);

but for some reason when I check the output via print_r I get an empty array()...

What am I missing?

laserlight

Let's see:
1. You have an array of country codes of the countries that you are concerned with.
2. You are a map of country codes to country names of all the countries in the world.
3. You want to display, in lexicographical order, the names of the countries that you are concerned with.

The solution should be obvious:
1. Filter out those countries for which you do not have a corresponding country code.
2. Sort the resulting array.

A simple implementation would be:

$results = array();
foreach ($countries as $key) {
    $results[] = $iso2name[$key];
}
sort($results);

If this was not obvious to you, then I suggest that you take some time to learn how to solve problems by programming, and perhaps take a basic course on algorithms and data structures.

zzz

Great!

...I've got two degrees already, none of each has anything to do with math of computers, unfortunately. I guess, I'll just have to learn this the hard way. Thanks for your help, as always.

laserlight

I guess, I'll just have to learn this the hard way.

There may be websites out there that present small programming problems for you to solve, with answers. Some of them, like Javabat (for Java, not PHP, unfortunately), even give instant feedback on your own attempted solutions.

zzz

I'll check it out.