What is the difference between =
, ==
, and ===
?
I think using one equal sign is to declare a variable while two equal signs are for a comparison condition and lastly three equal signs are for comparing values of declared variables.
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0 Answer
For advanced PHP users, knowing the difference between ==
and ===
and asking themselves "is it faster to compare with ==
or with ===
when I'm sure that both the operands are the same type?"
The short and general answer is:
For the ones interested in benchmarking it themselves, you can use the following code I wrote ad-hoc and try different values for $a
and $b
:
\nCOMPARE == (FIRST TRY): " . number_format($time_two_a, 3) . " seconds";
print "
\nCOMPARE == (SECOND TRY): " . number_format($time_two_b, 3) . " seconds";
print "
\nCOMPARE === (FIRST TRY): " . number_format($time_three_a, 3) . " seconds";
print "
\nCOMPARE === (SECOND TRY): " . number_format($time_three_b, 3) . " seconds";
?>
NOTE: The comparison is valid only when each "FIRST TRY" is very close to its "SECOND TRY". If they are significantly different, it means that the processor was busy doing something else while executing the comparisons and so the results are unreliable and the benchmark should be run again.
=
is the assignment operator ==
is the comparison operator (checks if
two variables have equal values)===
is the identical comparison
operator (checks if two variables
have equal values and are of the same
type).= assignment operator
== checks if two variables have the same value
=== checks if two variables have the same value AND if their types are the same
The = operator signs the value to a variable $six = 6; value 6 is assigned to variable $six
== operator check if the value of both variables is equal and mostly used in conditions like if statements
$a = 2;
$b = 2;
if ($a == $b) {
echo both variables have the same value;
}
=== operator similar to == (check if the value equals) and also check if both of same data type
$a = 2;
$b = "2";
if ($a === $b) {
echo "both variable have same value and of same data type";
} else {
echo 'both variable is either not equal or not of same data type';
}
// here $a is of type int whereas $b is of type string. So here the output
You have =
the , ==
the and ===
the .
$a = $b Assign Sets $a to be equal to $b.
$a == $b Equal TRUE if $a is equal to $b.
$a === $b Identical TRUE if $a is equal to $b, and they are of the same type. (introduced in PHP 4)
For more info on the need for ==
and ===
, and situations to use each, look at the docs.
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