Comparing NumPy arange and custom range function for producing ranges with decimal increments

Question

Here\'s a custom function that allows stepping through decimal increments:

def my_range(start, stop, step):
    i = start
    while i < stop:
        yiel         


        

Answer 1

While arange does step through the range in a slightly different way, it still has the float representation issue:

In [1358]: np.arange(0,1,0.1)
Out[1358]: array([ 0. ,  0.1,  0.2,  0.3,  0.4,  0.5,  0.6,  0.7,  0.8,  0.9])

The print hides that; convert it to a list to see the gory details:

In [1359]: np.arange(0,1,0.1).tolist()
Out[1359]: 
[0.0,
 0.1,
 0.2,
 0.30000000000000004,
 0.4,
 0.5,
 0.6000000000000001,
 0.7000000000000001,
 0.8,
 0.9]

or with another iteration

In [1360]: [i for i in np.arange(0,1,0.1)]  # e.g. list(np.arange(...))
Out[1360]: 
[0.0,
 0.10000000000000001,
 0.20000000000000001,
 0.30000000000000004,
 0.40000000000000002,
 0.5,
 0.60000000000000009,
 0.70000000000000007,
 0.80000000000000004,
 0.90000000000000002]

In this case each displayed item is a np.float64, where as in the first each is float.