PHP === and ? and : symbol meaning

Question

This is an extract from a WebSocket client, what does the following code line mean/do ?

$frameHead[1] = ($masked === true) ? $payloadLength + 128 : $payloadLength;

I read it this way (check below)

If Masked == True Then $frameHeadHead[1] = $payloadLength + 128 / $payloadLength

I don't understand the ($masked === true) as well as I dont understand the : $payLoadLength; (what is the : symbol for ?)

And what if Masked == False ? There is no result ?

Please search properly before you ask a question. – Sankalp Srivastava Jul 23 '14 at 05:14 — Sankalp Srivastava, Jul 23 '14 at 05:14

Rahul Tripathi · Accepted Answer · 2014-07-23T05:15:06.833

7

That(?:) is called the ternary operator.

(condition) ? /* if condition is true then return this value */ 
            : /* if condition is false then return this value */ ;

Also === compares the internal object id of the objects. It is used for strict comparison. "===" means that they are identical.

On a side note:

Note: Please note that the ternary operator is an expression, and that it doesn't evaluate to a variable, but to the result of an expression. This is important to know if you want to return a variable by reference. The statement return $var == 42 ? $a : $b; in a return-by-reference function will therefore not work and a warning is issued in later PHP versions.

edited Jul 23 '14 at 05:15

answered Jul 23 '14 at 05:09

Rahul Tripathi

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3

+1 for actually giving the name when all the other answers don't even mention it. – Joe DF Jul 23 '14 at 05:12
About `===` it is strict comparison which checks for data types as well – Mr. Alien Jul 23 '14 at 05:12

score 5 · Answer 2 · answered Jul 23 '14 at 05:11

5

$frameHead[1] = ($masked === true) ? $payloadLength + 128 : $payloadLength;

it  conditional statement like if and else  

 if($masked === true){ $payloadLength + 128 } else {$payloadLength;}

answered Jul 23 '14 at 05:11

karan

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why down vote reason ?????????????? – karan Jul 23 '14 at 05:17
poorly formatted, for one. – Eric Brown Jul 23 '14 at 05:35
Ok thanks.But please prefer on logic because your problem solve then our purpose solve boss. – karan Jul 23 '14 at 05:45

score 3 · Answer 3 · answered Jul 23 '14 at 05:11

first: the === checks if both the value and the type equal (so while false==0 is true, false===0 isn't). the reverse would be !==.

the var=bool ? value1 : value2 statement is the same as:

if(bool){
  var=value1;
}else{
  var=value2;
}

so your line translates to:

if($masked===true){
  $frameHead[1] = $payloadLength + 128;
}else{
  $frameHead[1] = $payloadLength;
}

score 2 · Answer 4 · answered Jul 23 '14 at 05:09

2

If Masked == True Then $frameHeadHead[1] = $payloadLength + 128 
Else $frameHeadHead[1] = $payloadLength

answered Jul 23 '14 at 05:09

score 2 · Answer 5 · answered Jul 23 '14 at 05:09

2

Its ternary operator.

$frameHead[1] = ($masked === true) ? $payloadLength + 128 : $payloadLength;

Means:

If Masked === True 

Then $frameHeadHead[1] = $payloadLength + 128 

Else

Then $frameHeadHead[1] = $payloadLength

answered Jul 23 '14 at 05:09

Manwal

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score 2 · Answer 6 · answered Jul 23 '14 at 05:14

2

Check below:

Why we use === instead of == ?

== is used for matching the value. === is used for matching the value with datatype.

More precisely, lets check one example -

99 == "99" // true
99 === "99" // false

(?:) mean

This is called a ternary operator. It means

$frameHead[1] = ($masked === true) ? $payloadLength + 128 : $payloadLength;

if ($masked === true) {
    $frameHead[1] = $payloadLength + 128;
} else {
   $frameHead[1] = $payloadLength;
}

answered Jul 23 '14 at 05:14

prava

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Why you guys down voting correct answers??? – Manwal Jul 23 '14 at 05:16
Don't encourage questions in which no effort are made. – Sankalp Srivastava Jul 23 '14 at 05:16
@Manwal, yes right :) don't understand the problem of others, why they do so. – prava Jul 23 '14 at 05:17
@SankalpSrivastava, then downvote the question, not the answer :). – prava Jul 23 '14 at 05:18

PHP === and ? and : symbol meaning

6 Answers6

Why we use === instead of == ?

(?:) mean