Difference between "==" and "strcmp" in PHP - php

Question

I was asked to create simulation array_keys function, but check equality "==" returns false.
But with "strcmp ($a, $b) == 0" return true.
class Utility
{
public function convertArrayKeys(array $array)
{
$i = 0;
$elements = [];
foreach ($array as $element=>$value) {
$elements[] = ' ' . $i++ . " => '" . $element . "'";
}
return 'array ( ' . implode(', ', $elements) . ', )';
}
public function testStrings(array $array)
{
$arrayOur = $this->convertArrayKeys($array);
$arrayPhp = var_export(array_keys($array),true);
if ($arrayOur == $arrayPhp){
echo 'They are identical :)';
} else {
echo 'They are not identical :(';
echo '<br>';
print_r(str_split($arrayOur));
echo '<br>';
print_r(str_split($arrayPhp));
}
}
}
View:
$repository = array('box'=>'blue', 'cube'=>'red', 'ball'=>'green');
$utility = new Utility();
echo "OUr array_keys: ";
echo $utility->convertArrayKeys($repository);
echo "<br />";
echo "PHP array_keys: ";
print_r (var_export(array_keys($repository)));
echo "<hr >";
echo "<br />";
echo $utility->testStrings($repository);
I would appreciate to know because

Answer 1

Edit: The reason that the two don't work in THIS instance is that your functions dont produce identical outputs: yours produces:
array ( 0 => 'box', 1 => 'cube', 2 => 'ball', )
where the php function produces:
array (
0 => 'box',
1 => 'cube',
2 => 'ball',
)
If you were to view that in the web browser i think the web browser renderer does whitespace trickery. However try putting uhh <pre> tags around it (or run in command line to check).
Basically == does more then compare the two values - the documentation suggests "after type juggling". You can get some weird things by comparing strings using ==. One good example is: '1e3' == '1000'. It is useful to use ==at times, but possibly not in conjunction with strings.
Strcmp also though doesn't return a true/false answer, but a -1, 0, 1 answer indicating which string is alphabetically in front of the other.
You should also look at === which can also have helpful uses, but personally I would stick with strcmp with strings.

Answer 2

Hi never use == in PHP. It will not do what you expect. Even if you are comparing strings to strings, PHP will implicitly cast them to floats and do a numerical comparison if they appear numerical.
try these you will know the reason
$something = 0;
echo ('password' == $something) ? 'true' : 'false';// true
$something = 0;
echo ('password' === $something) ? 'true' : 'false'; // false
echo strcmp('password123',$something); // 1

Answer 3

Because they are not arrays, rather they are strings. Arrays are not created like this. you are doing it wrong. Were they arrays then
if ($arrayOur == $arrayPhp)
would have evaluated to true. But they are just strings and
"strcmp ($a, $b) == 0"
Does not return true, because there are whitespaces in the first string,
return 'array ( ' . implode(', ', $elements) . ', )';
You are doing it completely wrong. You need to correct your approach.