matplotlib分散失败并出现错误:'c'参数包含n个元素，不适用于大小为n的'x'，大小为n的'y' [英] matplotlib scatter fails with error: 'c' argument has n elements, which is not acceptable for use with 'x' with size n, 'y' with size n

问题描述

我正在尝试使用 matplotlib 创建一个散点图，其中每个点都有一个特定的颜色值.

I am trying to create a scatter plot using matplotlib where each point has a specific color value.

我缩放值，然后在左"和右"颜色之间应用 alpha 混合.

I scale the values and then apply alpha blending between a 'left' and a 'right' color.

# initialization
from matplotlib import pyplot as plt
from sklearn.preprocessing import MinMaxScaler
import numpy as np

values = np.random.rand(1134)

# actual code
colorLeft = np.array([112, 224, 112])
colorRight = np.array([224, 112, 112])
scaled = MinMaxScaler().fit_transform(values.reshape(-1, 1))
colors = np.array([a * colorRight + (1 - a) * colorLeft for a in scaled], dtype = np.int64)
# check values here
f, [sc, other] = plt.subplots(1, 2)
sc.scatter(np.arange(len(values)), values, c = colors)

然而最后一行给出了错误:

However the last line gives the error:

'c' 参数有 1134 个元素，不能与大小为 1134 的 'x' 和大小为 1134 的 'y' 一起使用

'c' argument has 1134 elements, which is not acceptable for use with 'x' with size 1134, 'y' with size 1134

分散文档表示参数c

c:颜色，颜色序列或颜色序列，可选

c : color, sequence, or sequence of color, optional

标记颜色.可能的值:

  A single color format string.
  A sequence of color specifications of length n.
  A sequence of n numbers to be mapped to colors using cmap and norm.
  A 2-D array in which the rows are RGB or RGBA.

我要在RGB值中使用最后一个选项的地方.

Where I want to use the last option with RGB values.

我用一些打印语句替换了 check values here 注释:

I replaced the check values here comment with some print statements:

print(values)
print(colors)
print(values.shape)
print(colors.shape)

给出了结果:

[0.08333333 0.08333333 0.08333333 ... 1.         1.         1.08333333]
[[112 224 112]
 [112 224 112]
 [112 224 112]
 ...
 [214 121 112]
 [214 121 112]
 [224 111 112]]
(1134,)
(1134, 3)

推荐答案

将颜色转换为具有 0 <= 颜色 <= 1 的浮点数组，它应该可以正常工作.

Convert colors to a float array with 0 <= colors <= 1 and it should work fine.

sc.scatter(np.arange(len(values))，values，c = colors/255)

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