PHP: What does the '&' character mean?

Question

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Reference - What does this symbol mean in PHP?

What does adding a '&' mean in this snippet I found?

$i = 10;
if($i&1){
    echo "$i is odd";
}
else {
    echo "$i is even";
}

Answer 1

It's the bitwise AND operator. in your case, it takes the binary representations of 10 and 1 and performs the logical AND operation on the individual bits.

Answer 2

That's a binray and. So for example 148 (binary 10010100) & 136 (binary 10001000) will be 128 (binary 10000000). So $i & 1 is either 1 (true) or 0 (false)