Time for action – computing the modulo

Let's call the previously mentioned functions:

1. The remainder function returns the remainder of the two arrays, element-wise. 0 is returned if the second number is 0:

   a = np.arange(-4, 4)
   print "Remainder", np.remainder(a, 2)

   The result of the remainder function is shown as follows:

   Remainder [0 1 0 1 0 1 0 1]
   

2. The mod function does exactly the same as the remainder function:

   print "Mod", np.mod(a, 2)

   The result of the mod function is shown as follows:

   Mod [0 1 0 1 0 1 0 1]
   

3. The % operator is just shorthand for the remainder function:

   print "% operator", a % 2

   The result of the % operator is shown as follows:

   % operator [0 1 0 1 0 1 0 1]
   

4. The fmod function handles negative numbers differently than mod, fmod, and % do. The sign of the remainder is the sign of the dividend, and the sign of the divisor has no influence on the results:

   print "Fmod", np.fmod(a, 2)

   The fmod result is printed as follows:

   Fmod [ 0 -1  0 -1  0  1  0  1]
   

What just happened?

We demonstrated...