What does >> mean in PHP?

Question

Consider:

echo 50 >> 4;

Output:

3

Why does it output 3?

Answer 1

As documented on php.org, the >> operator is a bitwise shift operator which shifts bits to the right:

$a >> $b - Shift the bits of $a $b steps to the right (each step means "divide by two")

50 in binary is 110010, and the >> operator shifts those bits over 4 places in your example code. Although this happens in a single operation, you could think of it in multiple steps like this:

• Step 1 - 00011001
• Step 2 - 00001100
• Step 3 - 00000110
• Step 4 - 00000011

Since binary 11 is equal to 3 in decimal, the code outputs 3.