Why won't my Python scatter plot work?

问题

I created a very simple scatter plot using pylab.

pylab.scatter(engineSize, fuelMile)
pylab.show()

The rest of the program isn't worth posting, because it's that line that's giving me the problem. When I change "scatter" to "plot" it graphs the data, but each point is part of a line and that makes the whole things a scribbly mess. I just want points, not a line, but I get this huge error message that ends with:

  File "C:\Python26\lib\site-packages\numpy\core\fromnumeric.py", line 1643, in amin
    return amin(axis, out)
TypeError: cannot perform reduce with flexible type

回答1:

I bet engineSize, fuelMile are stings, try printing them, if that is the case, you have to convert them to float before passing them as arguments to scatter

floatval = float(strval)

回答2:

Okay, so since this works, something must be wrong with your inputs. Clearly you need to post more, unless this "answer" solves your problem:

>>> import pylab
>>> pylab.scatter([500, 550, 700, 1100], [5.5, 6.5, 3.1, 9.7])
<matplotlib.collections.RegularPolyCollection object at 0x036F5610>
>>> pylab.show()
(graphing-type stuff ensues)

来源：https://stackoverflow.com/questions/1746312/why-wont-my-python-scatter-plot-work