Member Avatar for super_alex

Can someone help me understand these operators.

Thanks.

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  • Latest Post Latest Post by rizvihaider72

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Several replies here distilled the core idea; and gave the short version and corrected 's confusing example. The concise takeaway: loose equality lets the language coerce types to try to match values, while strict equality requires type and value to match. That rule applies in both PHP and JavaScript, but the coercion rules differ, so examples that "look the same" can behave very differently across languages.

PHP notes and gotchas — loose comparisons can produce surprising matches because non-numeric strings and booleans are converted during comparison. Common defensive measures are using === when type matters, explicitly casting ((int), (bool), strval()), and using strict mode where available (for example in_array($needle, $haystack, true)). Examples:

<?php
var_dump('0' == false);    // true
var_dump('0' === false);   // false
var_dump('foo' == 0);      // true — 'foo' converts to 0 in numeric context

JavaScript notes — similar operator names but different rules. == follows a set of coercion steps (so null == undefined is true, 0 == false is true), while === is identity. NaN and -0 are special: NaN === NaN is false, Object.is can be used to distinguish NaN and -0. Examples:

console.log(null == undefined);   // true
console.log(null === undefined);  // false

console.log(0 == false);          // true
console.log(0 === false);         // false

console.log(NaN === NaN);         // false
console.log(Object.is(NaN, NaN)); // true

Practical guidance synthesizing thread contributions: prefer strict equality (===) unless a specific loose-coercion behavior is required and documented; when accepting external input, normalize types first; use language tools (var_dump, typeof, Object.is) to inspect values during debugging. For JavaScript equality details, see the MDN summary: MDN: Equality comparisons and sameness.

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All 6 Replies

Member Avatar for terabyte

$i = 10;
$t = 5+5;

$i == $t TRUE
$i === $t FALSE

Member Avatar for mschroeder

That is an incorrect example

<?php
$a = 10;
$b = 5+5;
$c = '5+5';

var_dump($a);
var_dump($b);
var_dump($c);
var_dump($a == $b);
var_dump($a === $b);
var_dump($b === $c);
int 10
int 10
string '5+5' (length=3)
boolean true
boolean true
boolean false
Member Avatar for network18

in short what all others are trying to explain you is '==' only checks the contents of both the operands for equality and '===' compares for types (of both operands) too.

Member Avatar for rizvihaider72

The difference between both of them is that :
"==" -> It only checks for equality without checking the datatype
"===" -> It checks for equality and also both the variables should be of same datatype

Edited by Ezzaral because: Snipped url. Please restrict personal links to your user signature.
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