Binary Conversion

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For more information, see Binary number on Wikipedia.

This tutorial goes over the basics of converting numbers into binary.

Explanation

Binary is a base-2 numerical system that uses 2 digits: 0 and 1.

Using binary in Scratch projects allows for very simple encoding and decoding of values. Because cloud variables hold a limited number of digits, converting a list of true / false values from binary to decimal will make use of the limited storage more efficiently.

Converting Numbers to Binary

Note that the numbers must be a non-negative positive integer.

This program requires two variables. The following variables are required:

• (binary)
• (i)

Once these variables have been created, the script below should be added to convert a number to binary:

define number to binary (num)
set [i v] to (num)
set [binary v] to ()
repeat until <(i) = (0)>
set [binary v] to (join ((i) mod (2))(binary))
set [i v] to ([floor v] of ((i) / (2)))
end

Likewise, the script below should be added to convert binary to numbers:

((0) + (join [0b] (binary)))

This script works because JavaScript (what Scratch is built on) interprets numbers with "0b" at the beginning as binary. Adding 0 to the string will convert the string into a number.

Padding Binary Numbers

The script below will convert a binary number into a binary number of equal value, adding 0's at the beginning so that the number has a multiple of 8 digits.

Example:

101 -> 00000101

11101 -> 00011101

11101110 -> 11101110

101101101 -> 0000000101101101

1101101101110 -> 0001101101101110

Script:

define pad binary number to have a multiple of 8 digits (bin)
set [binary v] to (bin)
repeat until <((length of (binary)) mod (8)) = (0)>
set [binary v] to (join (0)(binary))

See Also

• Binary number on Wikipedia