What is $a & $b and $a | $b in php?

Question

What happend $a & $b and $a | $b in php ?

$a = 11;
$b = 7;
echo $a & $b;

In the above php code it will give result 3 How it will calculate 3 ?

$a = 11;
$b = 7;
echo $a | $b;

In the above php code it will give result 15 How it will calculate 15?

Explain me both condition in php?

Answer 1

What's happening here is something called Bitwise Operators . It's more often used in much lower level languages, and it's one of the very simplest things a computer can do. Most computation is built on top of it. So what is it? Well, & is the Bitwise AND operator, and | is the Bitwise OR operator. You can test them with this online tool . But let's breakdown how it works.

AND Operator

Take two binary strings and any 1 's that aren't in both binaries, the the same place, become a 0 .

7 is 111 11 is 1011

So if you perform an AND on them, you get something like this

0111 &
1011 =
0011

0011 in Decimal is 3 . You get 0011 because only the last two places are BOTH 1 .

OR Operator

OR is basically the opsite. If a position in either binary is 1 , then the output is 1 . So when you perform it on 7 and 11 , you'll get

1011 |
0111 =
1111

And 1111 is 15 in decimal

Answer 2

In binary, 11 is 00001011 and 7 is 00000111 (showing only relevant 8 bits for simplicity).

---

So 11 & 7 (bitwise AND)

00001011
00000111 & matching only where both matching bits are `1`
--------
00000011

which is the binary for 3

---

So 11 | 7 11 | 7 (bitwise OR)

00001011
00000111 | matching where either (or both) bits is `1`
--------
00001111

which is the binary for 15