In PHP What Does |= Mean, That Is Pipe Equals (Not Exclamation)

In PHP what does |= mean, That is pipe equals (not exclamation)

php pipe equals for number

It would convert into binary when you pass | to values. Please refer for more What Does Using A Single Pipe '|' In A Function Argument Do?

Explanation:

Decimal             Binary
101                 1100101
7                   111

OR (|) operation in these values:

64  32  16  8  4  2  1  =   Value
1   1   0   0  1  0  1  =   101
               1  1  1  =   7
-------------------------------
1   1   0   0  1  1  1  =   103

How |= PHP Operator work?

$value |= 9;

$value = 9 | $value;

which is

$value = 9 | 10;

and | is the bitwise or operator(1|0 is 1, 1|0 is 1, everything else is 0): http://www.php.net/manual/en/language.operators.bitwise.php, so you have:

$value = 00001001 | 00001010;

and that gives

$value = 00001011;

which is 11

What Does Using A Single Pipe '|' In A Function Argument Do?

Bitwise operators

Bitwise operators modify the bits of the values involved. A bitwise OR basically ORs together each bit of both the left and right argument. For example:

5 | 2

Would translate to bits/binary as:

101 | 10

Which would result in:

Because:

1 || 0 = 1
0 || 1 = 1
1 || 0 = 1

And as an Integer that is the representation of 7 which is exactly what you get if you:

echo 5 | 2;

In the words of Eddie Izzard... Flag!

As Ignacio states, this is most often used in PHP (and other langauges) as a way to combine multiple flags. Each flag is usually defined as a constant whose value is normally set to an integer that represents just one bit at a different offset:

define('FLAG_A', 1); /// 0001
define('FLAG_B', 2); /// 0010
define('FLAG_C', 4); /// 0100
define('FLAG_D', 8); /// 1000

Then when you OR these together they operate each on their own bit offset and will never collide:

FLAG_A | FLAG_C

Translates to:

1 | 100

So you end up turning on:

Which represents the integer 5.

Then all the code has to do—the code that will be reacting to the different flags being set—is the following (using a bitwise AND):

$combined_flags = FLAG_A | FLAG_C;

if ( $combined_flags & FLAG_A ) {
  /// do something when FLAG_A is set
}

if ( $combined_flags & FLAG_B ) {
  /// this wont be reached with the current value of $combined_flags
}

if ( $combined_flags & FLAG_C ) {
  /// do something when FLAG_C is set
}

At the end of the day it just makes things easier to read by having named constants, and generally more optimal by relying on integer values rather than strings or arrays. Another benefit of using constants is that if they are ever mistyped when used, the compiler is in a better situation to tell and to throw a warning... if a string value is used it has no way of knowing that anything is wrong.

define('MY_FLAG_WITH_EASY_TYPO', 1);

my_function_that_expects_a_flag( MY_FLAG_WITH_EASY_TPYO );

/// if you have strict errors on the above will trigger an error

my_function_that_expects_a_flag( 'my_string_with_easy_tpyo' );

/// the above is just a string, the compiler knows nowt with 
/// regard to it's correctness, so instead you'd have to
/// code your own checks.

PHP operator |= explain

$mask |= 10 means $mask = $mask | 10. '|' operator is called bitwise operator.
Follow the example how bitwise operator works.

$mask =$mask | 10
      = 5 | 10
Firstly we have to convert the decimal to binary.
128 64 32 16 8 4 2 1
               1 0 1 =>5
             1 0 1 0 => 10
So for 5| 10
Output will be 8+4+2+1 =15

Here we need to add all decimal number that is under 1 bit.

Another example For 10 | 10

128 64 32 16 8 4 2 1
             1 0 1 0=>10
             1 0 1 0 => 10

So the result of 10 | 10 is

= 8+2 = 10

For more information visit this link
http://www.w3resource.com/php/operators/bitwise-operators.php

What does |= (single pipe equal) and &=(single ampersand equal) mean

They're compound assignment operators, translating (very loosely)

x |= y;

into

x = x | y;

and the same for &. There's a bit more detail in a few cases regarding an implicit cast, and the target variable is only evaluated once, but that's basically the gist of it.

In terms of the non-compound operators, & is a bitwise "AND" and | is a bitwise "OR".

EDIT: In this case you want Folder.Attributes &= ~FileAttributes.System. To understand why:

~FileAttributes.System means "all attributes except System" (~ is a bitwise-NOT)
& means "the result is all the attributes which occur on both sides of the operand"

So it's basically acting as a mask - only retain those attributes which appear in ("everything except System"). In general:

|= will only ever add bits to the target
&= will only ever remove bits from the target

Does the 'bang' operator (!) in VB6 mean anything if it is merely on the end of a variable/number? If so, what does it mean?

It's no an operator, it's a type indicator. An Exclamation/Bang at the end of the name indicates a variable that can hold single precision floating point value. Here's a list of VB type indicators (may not be complete):

$ - string 
% - integer 
& - long integer 
! - single precision floating point
# - double precision floating point 
@ - currency

What does this symbol mean in JavaScript?

See the documentation on MDN about expressions and operators and statements.

Basic keywords and general expressions

`this` keyword:

How does the "this" keyword work, and when should it be used?

`var x = function()` vs. `function x()` — Function declaration syntax

var functionName = function() {} vs function functionName() {}

`(function(){`…`})()` — IIFE (Immediately Invoked Function Expression)

What is the purpose?, How is it called?
Why does (function(){…})(); work but function(){…}(); doesn't?
(function(){…})(); vs (function(){…}());
shorter alternatives:
- !function(){…}(); - What does the exclamation mark do before the function?
- +function(){…}(); - JavaScript plus sign in front of function expression
- !function(){ }() vs (function(){ })(), ! vs leading semicolon
(function(window, undefined){…}(window));

`someFunction()()` — Functions which return other functions

Two sets of parentheses after function call

`=>` — Equal sign, greater than: arrow function expression syntax

What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?

`|>` — Pipe, greater than: Pipeline operator

What does the "|>" operator do in JavaScript?

`function`, `yield`, `yield` — Star after `function` or `yield`: generator functions

What is "function*" in JavaScript?
What's the yield keyword in JavaScript?
Delegated yield (yield star, yield *) in generator functions

`[`…`]`, `[ value ]`, `Array()` — Square brackets: array notation

What’s the difference between "Array()" and "[]" while declaring a JavaScript array?
What is array literal notation in javascript and when should you use it?

If the square brackets appear on the left side of an assignment ([a] = ...), or inside a function's parameters, it's a destructuring assignment.

`{`…`}`, `{ key: value }`, `{ [key]: value }` — Curly brackets: object literal syntax (not to be confused with blocks)

What do curly braces in JavaScript mean?
Javascript object literal: what exactly is {a, b, c}?
What do square brackets around a property name in an object literal mean?
How does this object method definition work without the "function" keyword? (ES2015 Method definitions)

If the curly brackets appear on the left side of an assignment ({ a } = ...) or inside a function's parameters, it's a destructuring assignment.

`…`${`…`}`…` — Backticks, dollar sign with curly brackets: template literals

What does this `…${…}…` code from the node docs mean?
Usage of the backtick character (`) in JavaScript?
What is the purpose of template literals (backticks) following a function in ES6?

`/`…`/` — Slashes: regular expression literals

Meaning of javascript text between two slashes

`$` — Dollar sign in regex replace patterns: `$$`, `$&`, $`, `$'`, `$n`

JavaScript replace() method dollar signs

`()` — Parentheses: grouping operator

MDN: Grouping operator

Property-related expressions

`obj.prop`, `obj[prop]`, `obj["prop"]` — Square brackets or dot: property accessors

JavaScript property access: dot notation vs. brackets?

`?.`, `?.[]`, `?.()` — Question mark, dot: optional chaining operator

Question mark after parameter
Null-safe property access (and conditional assignment) in ES6/2015
Optional Chaining in JavaScript
Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript?
Is there a "null coalescing" operator in JavaScript?

`::` — Double colon: bind operator

JavaScript double colon (bind operator)

`new` operator

What is the 'new' keyword in JavaScript?
What is "new.target"?

`...iter` — Three dots: spread syntax; rest parameters

(...rest) => {} — What is the meaning of “…args” (three dots) in a function definition?
fn(...args) — What is the meaning of “foo(…arg)” (three dots in a function call)?
[...iter] — javascript es6 array feature […data, 0] “spread operator”
{...props} — Javascript Property with three dots (…), What does the '…rest' stand for in this object destructuring?

Increment and decrement

`++`, `--` — Double plus or minus: pre- / post-increment / -decrement operators

++someVariable vs someVariable++ in Javascript

Unary and binary (arithmetic, logical, bitwise) operators

`delete` operator

What is the purpose of the delete operator in Javascript?

`void` operator

What does `void 0` mean?

`+`, `-` — Plus and minus: addition or concatenation, and subtraction operators; unary sign operators

What does = +_ mean in JavaScript, Single plus operator in javascript
What's the significant use of unary plus and minus operators?
Why is [1,2] + [3,4] = "1,23,4" in JavaScript?
Why does JavaScript handle the plus and minus operators between strings and numbers differently?

`|`, `&`, `^`, `~` — Single pipe, ampersand, circumflex, tilde: bitwise OR, AND, XOR, & NOT operators

What do these JavaScript bitwise operators do?
How to: The ~ operator?
Is there a & logical operator in Javascript
What does the "|" (single pipe) do in JavaScript?
What does the operator |= do in JavaScript?
What does the ^ (caret) symbol do in JavaScript?
Using bitwise OR 0 to floor a number, How does x|0 floor the number in JavaScript?
Why does ~1 equal -2?
What does ~~ ("double tilde") do in Javascript?
How does !!~ (not not tilde/bang bang tilde) alter the result of a 'contains/included' Array method call? (also here and here)

`%` — Percent sign: remainder operator

What does % do in JavaScript?

`&&`, `||`, `!` — Double ampersand, double pipe, exclamation point: logical operators

Logical operators in JavaScript — how do you use them?
Logical operator || in javascript, 0 stands for Boolean false?
What does "var FOO = FOO || {}" (assign a variable or an empty object to that variable) mean in Javascript?, JavaScript OR (||) variable assignment explanation, What does the construct x = x || y mean?
Javascript AND operator within assignment
What is "x && foo()"? (also here and here)
What is the !! (not not) operator in JavaScript?
What is an exclamation point in JavaScript?

`??` — Double question mark: nullish-coalescing operator

How is the nullish coalescing operator (??) different from the logical OR operator (||) in ECMAScript?
Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript?
Is there a "null coalescing" operator in JavaScript?

`**` — Double star: power operator (exponentiation)

x ** 2 is equivalent to Math.pow(x, 2)
Is the double asterisk ** a valid JavaScript operator?
MDN documentation

Equality operators

`==`, `===` — Equal signs: equality operators

Which equals operator (== vs ===) should be used in JavaScript comparisons?
How does JS type coercion work?
In Javascript, <int-value> == "<int-value>" evaluates to true. Why is it so?
[] == ![] evaluates to true
Why does "undefined equals false" return false?
Why does !new Boolean(false) equals false in JavaScript?
Javascript 0 == '0'. Explain this example
Why false == "false" is false?

`!=`, `!==` — Exclamation point and equal signs: inequality operators

!= vs. !==
What is the difference between != and !== operators in JavaScript?

Bit shift operators

`<<`, `>>`, `>>>` — Two or three angle brackets: bit shift operators

What do these JavaScript bitwise operators do?
Double more-than symbol in JavaScript
What is the JavaScript >>> operator and how do you use it?

Conditional operator

…`?`…`:`… — Question mark and colon: conditional (ternary) operator

Question mark and colon in JavaScript
Operator precedence with JavaScript's ternary operator
How do you use the ? : (conditional) operator in JavaScript?

Assignment operators

`=` — Equal sign: assignment operator

What is the difference between the `=` and `==` operators and what is `===`? (Single, double, and triple equals)

This symbol is also used for default parameters or default values in a destructuring assignment:

what does (state = {}) => state means
What does ({"key": "value"} = {}) syntax mean inside a JavaScript function

`%=` — Percent equals: remainder assignment

Having Confusion with Modulo operator

`+=` — Plus equals: addition assignment operator

How does += (plus equal) work?

`&&=`, `||=`, `??=` — Double ampersand, pipe, or question mark, followed by equal sign: logical assignments

What purpose do &&=, ||= and ??= serve?
Replace a value if null or undefined in JavaScript
Set a variable if undefined
Ruby’s ||= (or equals) in JavaScript?
Original proposal
Specification

`<<=`, `>>=`, `>>>=`, `&=`, `^=`, `|=` — Double less than, double greater than, triple greater than, ampersand, caret, or pipe followed by equal sign: bitwise assignments

What do these JavaScript bitwise operators do?

Destructuring

of function parameters: Where can I get info on the object parameter syntax for JavaScript functions?
of arrays: Multiple assignment in JavaScript? What does `[ a, b, c ] = [ 1, 2, 3 ]` mean?
of objects/imports: Javascript object bracket notation ({ Navigation } =) on left side of assign

Comma operator

`,` — Comma operator (not to be confused with the comma used in variable declarations)

What does the comma operator do in JavaScript?
Comma operator returns first value instead of second in argument list?
When is the comma operator useful?

Control flow

`{`…`}` — Curly brackets: blocks (not to be confused with object literal syntax)

JavaScript curly braces with no function or json

Declarations

`var`, `let`, `const` — Declaring variables

What is the difference between "let" and "var"?
Are there constants in JavaScript?
What is the temporal dead zone?
var a, b; — Comma used in variable declarations (not to be confused with the comma operator): JavaScript variable definition: Commas vs. Semicolons

Label

`label:` — Colon: labels

What does the JavaScript syntax foo: mean?
What does ':' (colon) do in JavaScript?

Other

`123n` — `n` after integer: BigInt

What does character 'n' after numeric literal mean in JavaScript?

`#` — Hash (number sign): Private methods or private fields

What does the # symbol do in JavaScript?

`_` — Underscore: separator in numeric literals

Javascript numeric separators?
Is there a Javascript equivalent to the Ruby syntax using underscores (e.g. 10_000 = 10000) to make larger integers human readable?