Python 如何使用颜色图为 Pandas DataFrame 的绘图着色
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How to use colormaps to color plots of Pandas DataFrames
提问by Guforu
I have a pd.DataFramelike this one:
我有一个pd.DataFrame这样的：
ColumnName
1
1
2
3
1
2
3
1
2
2
I can plot it with df['ColumnName'].plot(style='o')
我可以用它来绘制 df['ColumnName'].plot(style='o')
How I can define different colors for the different values in the column (for example red for value 1, green for 2, orange for 3). I know it has to do with colormap, but how I can use it?
我如何为列中的不同值定义不同的颜色（例如，红色代表值 1，绿色代表 2，橙色代表 3）。我知道它与 有关colormap，但我如何使用它？
An solution is to construct a new DataFramewith the columns of every value. But these values are sorted and I want have exactly this sequence just colored in the different colors.
一个解决方案是DataFrame用每个值的列构造一个新的。但是这些值是排序的，我想要这个序列只是用不同的颜色着色。
采纳答案by LondonRob
To plot the first column from your dataframe, try something like this:
要绘制数据框中的第一列，请尝试以下操作：
from matplotlib import cm
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
df = pd.DataFrame(np.random.randint(20, size=20))
cmap = cm.get_cmap('Spectral') # Colour map (there are many others)
fig, ax = plt.subplots(1)
# Now here's the plot. range(len(df)) just makes the x values 1, 2, 3...
# df[0] is then the y values. c sets the colours (same as y values in this
# case). s is the marker size.
ax.scatter(range(len(df)), df[0], c=df[0], s=120, cmap=cmap, edgecolor='None')
plt.show()
Which results in:
结果是：
