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PHP PHP Arrays and Control Structures PHP Arrays Multidimensional Arrays

james tarala
james tarala
1,370 Points
Posted by james tarala
james tarala
1,370 Points

Multiple array elements not passing.

I can't seem to figure out why the two elements in the array aren't passing; the email address and the name. I presume it's because of the colon. I am sure I am missing something simple. Any help will be appreciated, so thanks in advance!

index.php 
<?php
//edit this array

$contacts [] = array(
  'name' => 'Alena Holligan',
  'email' => 'alena.holligan@teamtreehouse.com'
  );
$contacts [] = array(
  'name' => 'Dave McFarland',
  'email' => 'dave.mcfarland@teamtreehouse.com'
  );
$contacts [] = array(
  'name' => 'Treasure Porth',
  'email' => 'treasure.porth@teamtreehouse.com'
  );
$contacts [] = array(
  'name' => 'Andrew Chalkley',
  'email' => 'andrew.chalkley@teamtreehouse.com'
  );

echo "<ul>\n";
//$contacts[0] will return 'Alena Holligan' in our simple array of names.
echo "<li>$contacts[0]['name'] : $contacts[0]['email']</li>\n";
echo "<li>$contacts[1]['name'] : $contacts[1]['email']</li>\n";
echo "<li>$contacts[2]['name'] : $contacts[2]['email']</li>\n";
echo "<li>$contacts[3]['name'] : $contacts[3]['email']</li>\n";
echo "</ul>\n";

?>
andren
andren
28,558 Points
andren
andren
28,558 Points

That answer shows how the challenge can be solved with string concatenation (using . to combine strings) but the challenge can be solved with string interpolation (including variables in double quoted strings) like you tried as well, which I give an example of in my answer below.

1 Answer

andren
andren
28,558 Points
andren
andren
28,558 Points

Actually this is a case of a somewhat common gotcha that PHP has regarding string interpolation in double quoted strings.

When PHP encounters a $ symbol in a double quoted string it has to guess where the variable actually stops. Normally it manages to do so fine on its own, but when you have a multidimensional array PHP will stop once it gets to the first pair of square brackets and then interpret the next set of brackets as pure text that is not related to the variable it should interpret, which is incorrect.

In order to tell PHP that you want both of the square brackets to be considered when it does string interpolation you have to wrap the the array variable in curly braces {} like this:

<?php
echo "<ul>\n";
//$contacts[0] will return 'Alena Holligan' in our simple array of names.
echo "<li>{$contacts[0]['name']} : {$contacts[0]['email']}</li>\n";
echo "<li>{$contacts[1]['name']} : {$contacts[1]['email']}</li>\n";
echo "<li>{$contacts[2]['name']} : {$contacts[2]['email']}</li>\n";
echo "<li>{$contacts[3]['name']} : {$contacts[3]['email']}</li>\n";
echo "</ul>\n";
?>

The curly braces tells PHP exactly where the variable starts and ends which will work correctly.

Alternatively you can also use string concatenation (combining strings with .) instead of using string interpolation with double quotes.

Edit: Fixed some typos and cleaned up some sections.

james tarala
james tarala
1,370 Points
james tarala
james tarala
1,370 Points

Thank you! That makes a lot of sense. Do you think there is a "best" out of the two examples? It seems the one you mentioned using the brackets is cleaner than adding a bunch of double-quotes.

andren
andren
28,558 Points
andren
andren
28,558 Points

No, I don't really think either way is objectively better than the other. They have the same effect so it's mostly down to personal preference whether you prefer string concatenation or string interpolation. In cases where you are inserting a lot of variables it would indeed get a bit annoying constantly having to open and close strings, but it's not that rare a practice.

I tend to go for string interpolation whenever possible since I (as you) think it is cumbersome to combine many string together when you can keep all the content within one, especially since it makes spacing a lot easier to deal with as well. But that is a personal preference of mine, and there are certainly people who disagree.

When you work on your own you can go with whatever approach you prefer, though it's worth noting that if you end up joining a programming team at some point then It's pretty common to have a coding style guideline that dictates whether you use string concatenation or string interpolation and other such things. This is to ensure that the code the team writes is consistent and easy for the others to read. So in that case you may not have a choice either way.