find the base 2 logarithm of a number in php

To find the base 2 logarithm of a number in PHP, you can use the log() function with a second argument of 2. This will return the logarithm of the number with a base of 2, effectively giving you the number of bits needed to represent the number in binary.

main.php
$num = 42;
$log = log($num, 2); // base 2 logarithm of 42
echo $log; // outputs 5.3923174227788
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In this example, we find the base 2 logarithm of the number 42, which is approximately 5.3923174227788. This means that 42 can be represented in binary using 6 bits (2^6 = 64, which is the smallest power of 2 greater than 42).