Difference between myVar[0] and myVar->{0}?

PHP
1

I just took over a PHP project and I’m currently sorting through some issues in the code I inherited. In a function that returns search results from ASK, the “raw results” are returned by a call to simplexml_load_file($url). The code that process these results looks like this:

$this->process($this->raw_results->Engine->{0}->ResultSet,“sponsored”);
$this->process($this->raw_results->Engine->{1}->ResultSet,“results”);

etc.

This seems to work fine on the live server. However, the code doesn’t work on my local Apache server. When I tried stepping through with Zend debugger, I noticed that ‘Engine’ is actually an array, and putting the two expressions above in my watch list yields ‘null’ or undefined values. However, if I change the code to:

$this->process($this->raw_results->Engine[0]->ResultSet,"sponsored");						
$this->process($this->raw_results->Engine[1]->ResultSet,"results");

I can see valid data in these expressions. However, the code still doesn’t work. If I do the following:

$this->process($this->raw_results->Engine[0]->ResultSet,"sponsored");						
$this->process($this->raw_results->Engine->{1}->ResultSet,"results");

The code works. So there is obviously some side-effect or nuance in “process()” which I need to deal with.

My question is, what are the differences between the two ([0] and ->{0})? As far as I can tell, the latter is a usage of PHP’s complex curly syntax, but it still doesn’t quite make sense to me. Is using curly brackets a valid way of accessing an array, and does it yield any differences than using square brackets?

Thx,

Helo

2

Hi, I’m not that familiar with PHP to know what that code is meant to do, however it looks to me like curly braces are being used incorrectly…


$string = 'abc';
echo $string{1}; // b
echo $string{0}; // a

$array = array('a', 'b', 'c');
echo $array[1]; // b
echo $array[0]; // a

$obj = json_decode('{"a" : "a", "b" : "b", "c" : "c"}');
echo $obj->{a}; // Use of undefined constant a - assumed 'a'

Turn on error reporting to see what is happening:

error_reporting(E_ALL);
ini_set(‘display_errors’, ‘On’);

3

AFAIK, like the above poster I’m not too adept but {} creates a variable definition.

<?php

$obj = null;
$obj->{'eh'} = 'I AM CANADIAN';

print $obj->eh; // I AM CANADIAN

var_dump($obj);

/* var_dump is...
object(stdClass)#1 (1) {
  ["eh"]=>
  string(13) "I AM CANADIAN"
}
*/
?>