python error "ValueError: Invalid vertices array"

Question

我是运行下面的代码，在制作绘图时出现以下错误。当我打印 cov 变量时，其中的数字用单引号括起来。我假设这是问题所在？当我尝试绘制 x 和 y 时，它工作得很好。我是新 python 用户。有什么建议么？谢谢！

#!/bin/python

import matplotlib.pyplot as plt
import matplotlib.cm as cm
import numpy as np
from sys import argv
#from numpy import array

#array = numpy.float64(array)

script, filename = argv

file = open(filename)

pos = []
cov = []

for line in file:
    if (line.split()[0])=='1':
        ch = int(line.split()[0])
        #adjpos = int(line.split()[1])
        pos.append(line.split()[1])
        cov.append(line.split()[2])

file.close()

print cov

x = [0, 1, 2, 3]
y = [5, 10, 5, 5]

print x
print y

fig = plt.figure(figsize=(16,3),edgecolor='w')
plt.scatter(pos,cov,marker='.',s=1)
plt.show()

Traceback (most recent call last):
  File "/Users/eflannery/Dropbox/plotSamFlags.py", line 37, in <module>
    plt.scatter(pos,cov,marker='.',s=1)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/matplotlib/pyplot.py", line 2557, in scatter
    ret = ax.scatter(x, y, s, c, marker, cmap, norm, vmin, vmax, alpha, linewidths, faceted, verts, **kwargs)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/matplotlib/axes.py", line 5876, in scatter
    self.add_collection(collection)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/matplotlib/axes.py", line 1445, in add_collection
    self.update_datalim(collection.get_datalim(self.transData))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/matplotlib/collections.py", line 160, in get_datalim
    offsets = transOffset.transform_non_affine(offsets)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/matplotlib/transforms.py", line 1925, in transform_non_affine
    self._a.transform(points))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/matplotlib/transforms.py", line 1415, in transform
    return affine_transform(points, mtx)
ValueError: Invalid vertices array.

Answer 1

数字需要转换为matplotlib可以使用的类型；现在它只是制作一个字符串列表，如 split() returns 一个字符串列表。您可以通过在读取文件时调用 int()（或 float()，如果数字不全是整数）来转换字符串来解决此问题，您已经在分配给 ch:

for line in file:
    if (line.split()[0])=='1':
        ch = int(line.split()[0])
        pos.append(int(line.split()[1]))
        cov.append(int(line.split()[2]))

Answer 2

如果数字周围有引号，则表示它们出现在字符串中，这很可能会导致问题。

在你的代码中

         pos.append(line.split()[1])
         cov.append(line.split()[2])

这会将数字作为字符串附加到列表 pos 和 cov，因此您应该执行上述操作并将它们转换为数字。

         pos.append(int(line.split()[1]))

python error "ValueError: Invalid vertices array"

python error "ValueError: Invalid vertices array"

python

scatter-plot