Plot string values in matplotlib

Question

I am using matplotlib for a graphing application. I am trying to create a graph which has strings as the X values. However, the using plot function expects a nu

Answer 1

I couldn't find a convenient way to accomplish that, so I resorted to this little helper function.

import matplotlib.pyplot as p
def plot_classes(x, y, plotfun=p.scatter, **kwargs):
    from itertools import count
    import numpy as np
    classes = sorted(set(x))
    class_dict = dict(zip(classes, count()))
    class_map = lambda x: class_dict[x]
    plotfun(map(class_map, x), y, **kwargs)
    p.xticks(np.arange(len(classes)), classes)

Then, calling plot_classes(data["class"], data["y"], marker="+") should work as expected.