Question

I wanted to concatenate 2 variables, and by error I typed another code and I got a strange result.

This is what looks like the code :

echo 'Hello World' | 'test';

Result : |e|o World

What the pipe sign do if not concatenated ?

Answer 1

According to the PHP manual

“|” is a “bitwise OR”. Bitwise operators allow evaluation and manipulation of specific bits within an integer.

 Example          Name                            Result
 $a | $b      Or (inclusive or)     Bits that are set in either $a or $b are set.

Example:

$a =    9;
$b =    10;
echo $a | $b;

This would output the number 11 as follows:

                                      1 Byte ( 8 bits )
Place Value            128    64    32    16    8    4    2    1
$a                       0     0     0     0    1    0    0    1    =    9
$b                       0     0     0     0    1    0    1    0    =   10
$a | $b                  0     0     0     0    1    0    1    1    =   11

If you notice we have 3 bits set, in the 8, 2, and 1 column.. add those up 8+2+1 and you get 11.

For mere string concatenation use the dot . operator.

Hope that clarifies it.