modulo

Can anyone explain how the modulo operator works in Python? I cannot understand why 3.5 % 0.1 = 0.1 . abarnert Actually, it's not true that 3.5 % 0.1 is 0.1 . You can test this very easily: >>> print(3.5 % 0.1) 0.1 >>> print(3.5 % 0.1 == 0.1) False In actuality, on most systems, 3.5 % 0.1 is 0.099999999999999811 . But, on some versions of Python, str(0.099999999999999811) is 0.1 : >>> 3.5 % 0.1 0.099999999999999811 >>> repr(3.5 % 0.1) '0.099999999999999811' >>> str(3.5 % 0.1) '0.1' Now, you're probably wondering why 3.5 % 0.1 is 0.099999999999999811 instead of 0.0 . That's because of the usual

Am I doing modulus wrong? Because in Java -13 % 64 is supposed to evaluate to -13 but I get 51 . Both definitions of modulus of negative numbers are in use - some languages use one definition and some the other. If you want to get a negative number for negative inputs then you can use this: int r = x % n; if (r > 0 && x < 0) { r -= n; } Likewise if you were using a language that returns a negative number on a negative input and you would prefer positive: int r = x % n; if (r < 0) { r += n; } Since "mathematically" both are correct: -13 % 64 = -13 (on modulus 64) -13 % 64 = 51 (on modulus 64)

As an example in pseudocode: if ((a mod 2) == 0) { isEven = true; } else { isEven = false; } Cody Hatch For non-negative integers, you can use the remainder operator % . For your exact example: if ((a % 2) == 0) { isEven = true; } else { isEven = false; } This can be simplified to a one-liner: isEven = (a % 2) == 0; martinatime Here is the representation of your pseudo-code in minimal Java code; boolean isEven = a % 2 == 0; I'll now break it down into its components. The modulus operator in Java is the percent character (%). Therefore taking an int % int returns another int. The double equals