What's the difference between if( $x=1 || $y=1) and if( $x=1 | $y=1) in PHP

Question

Possible Duplicate:
Reference - What does this symbol mean in PHP?

Whats the difference between these two in php?

 if( $x==1 || $y==1)   if( $x==1 && $y==1)

vs. (respectively)

 if( $x==1 | $y==1)    if( $x==1 & $y==1)

To my knowledge they both work the same | vs. || in php. But there has to be a difference!!!

Do you mean `=` (assignment) or `==` (comparison)? – mathematical.coffee Nov 20 '12 at 03:45 — mathematical.coffee, Nov 20 '12 at 03:45
@mathematical.coffee i mean == (comparison)... I fixed it! – Arian Faurtosh Nov 20 '12 at 03:46 — Arian Faurtosh, Nov 20 '12 at 03:46

score 6 · Accepted Answer · answered Nov 20 '12 at 03:51

6

|| and && are boolean operators, they take 2 arguments, convert each to a boolean, then return true or false.

| and & are bitwise operators. They convert their arguments to binary and compare each bit. They return a binary number.

answered Nov 20 '12 at 03:51

gen_Eric

223,194
41
299
337

clear and concise! perfect! Thanks! – Arian Faurtosh Nov 20 '12 at 16:28
1

@Arian, also note that `||` and `&&` evaluate their arguments from left-to-right and short-circuit as soon as possible, that is, if the left expression is true, `||` will not evaluate anything to the right (same for false and `&&`). – acelent Nov 25 '12 at 00:32

score 2 · Answer 2 · answered Nov 20 '12 at 03:45

2

One is using conditional or and and and the other is using bitwise or and and.

answered Nov 20 '12 at 03:45

alex

479,566
201
878
984

NullPoiиteя · Answer 3 · 2012-11-20T03:52:58.053

1

|| this is condition OR
| this is bit wise or

$a | $b Or (inclusive or) Bits that are set in either $a or $b are set
$a & $b And Bits that are set in both $a and $b are set.

.

              if( $x==1 || $y=1)             if( $x==1 && $y==1)

  if body --> if one of them is true            both is true

edited Nov 20 '12 at 03:52

answered Nov 20 '12 at 03:46

NullPoiиteя

56,591
22
125
143

Samuel Cook · Answer 4 · 2012-11-20T03:51:41.083

0

First off: if( $x=1 || $y=1) will set $x to the value of 1 and $y to the value of 1.

The correct syntax would be:

if( $x==1 || $y==1)

The difference can be better expressed with words:

if( $x==1 OR $y==1) `if( $x==1 AND $y==1)

The double ampersand and double pipes are known as logical operators. see more here

The single ampersand and single pipes are bitwise statements. see more here

edited Nov 20 '12 at 03:51

answered Nov 20 '12 at 03:46

Samuel Cook

16,620
7
50
62

It is valid syntax; the statement `$x=1` returns 1 (assigns 1 to `$x`) and likewise with `$y`, and these are then bitwise OR or bitwise AND together. – mathematical.coffee Nov 20 '12 at 03:47
which is what i stated in the first sentence – Samuel Cook Nov 20 '12 at 03:48
Oh, I misinterpreted your last sentence, I see. – mathematical.coffee Nov 20 '12 at 03:49

score 0 · Answer 5 · answered Nov 20 '12 at 04:17

Documentation is your friend. && and || are logical operators. You can read more about them here.

I highly suggest you read about operator precedence and learn why && vs and and || vs or are different. Learn when one is more appropriate than the other. Essentially = has higher precedence than and and or, but lower precedence than && and ||. Example #1 of the logical operators section does a good job of explaining this.

With other languages you just have && and ||, not and and or.

& and | are bitwise operators. You can read about them here.

Typical usage for bitwise operators are flags. One common use is PHP's error_reporting setting.

What's the difference between if( $x=1 || $y=1) and if( $x=1 | $y=1) in PHP

5 Answers5