Easiest way to plot values as symbols in scatter plot?

Question

In an answer to an earlier question of mine regarding fixing the colorspace for scatter images of 4D data, Tom10 suggested plotting values as symbols in order to double-check my data. An excellent idea. I've run some similar demos in the past, but I can't for the life of me find the demo I remember being quite simple.

So, what's the easiest way to plot numerical values as the symbol in a scatter plot instead of 'o' for example? Tom10 suggested plt.txt(x,y,value)- and that is the implementation used in a number of examples. I however wonder if there's an easy way to evaluate "value" from my array of numbers? Can one simply say: str(valuearray) ?

Do you need a loop to evaluate the values for plotting as suggested in the matplotlib demo section for 3D text scatter plots?

Their example produces:

However, they're doing something fairly complex in evaluating the locations as well as changing text direction based on data. So, is there a cute way to plot x,y,C data (where C is a value often taken as the color in the plot data- but instead I wish to make the symbol)?

Again, I think we have a fair answer to this- I just wonder if there's an easier way?

Answer 1

The easiest way I've seen to do this is:

for x, y, val in zip(x_array, y_array, val_array):
    plt.text(x, y, val)

Also, btw, you suggested using str(valarray), and this, as you may have noticed doesn't work. To convert an array of numbers to a sequence of strings you could use

valarray.astype(str)

to get a numpy array, or,

[str(v) for v in valarray]

to get a Python list. But even with valarray as a proper sequence of strings, plt.text won't iterate over it's inputs.