Python matplotlib 绘制所有列的 csv 文件
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matplotlib plot csv file of all columns
提问by user2095624
I have a csv file which contains 20 columns. Right now I can plot using this code taking first column as x axis and rest of them as y axis.
我有一个包含 20 列的 csv 文件。现在我可以使用此代码进行绘图，将第一列作为 x 轴，其余作为 y 轴。
import numpy as np
import matplotlib.pyplot as plt
data = np.genfromtxt('cs.csv',delimiter=',', dtype = float)
a = [row[0] for row in data]
b = [row[1] for row in data]
c = [row[2] for row in data]
fig = plt.figure()
ax = fig.add_subplot(111, axisbg = 'w')
ax.plot(a,b,'g',lw=1.3)
ax.plot(a,c,'r',lw=1.3)
plt.show()
The problem is here I have to define all the columns by using
问题是我必须使用定义所有列
a = [row[0] for row in data]
a = [row[0] for row in data]
this code for all columns one by one. What I want actually to have some method so that it can plot all 19 columns taking first column as x axis constant and plot them in a single window. Any help please.
此代码一一显示所有列。我实际上想要有一些方法，以便它可以绘制所有 19 列，将第一列作为 x 轴常量并将它们绘制在单个窗口中。请任何帮助。
采纳答案by atomh33ls
How about this:
这个怎么样：
[plt.plot(data[0],data[x]) for x in range(1,len(data[:,0]))]
回答by Matti John
You could try using pandas, which uses matplotlib for plotting. For example, if you have a CSV like this:
您可以尝试使用pandas，它使用 matplotlib 进行绘图。例如，如果您有这样的 CSV：
a,b,c
20,2,5
40,6,8
60,4,9
You can plot columns b& clike this:
您可以绘制列b&c像这样：
import pandas as pd
df = pd.DataFrame.from_csv('test.csv', parse_dates=False)
df.b.plot(color='g',lw=1.3)
df.c.plot(color='r',lw=1.3)
The first column, is used as the index & x-axis by default. See the plotting documentationfor more details.
第一列默认用作索引和 x 轴。有关更多详细信息，请参阅绘图文档。
回答by Jonny Brooks
As Matti John said, Pandas is the way forward and you can do what you asked even easier. Assuming your CSV is a similar form to the one he posted, you can plot all columns (except the first) against the first column like this:
正如 Matti John 所说，Pandas 是前进的方向，您可以更轻松地完成您的要求。假设您的 CSV 格式与他发布的格式相似，您可以针对第一列绘制所有列（第一列除外），如下所示：
import pandas as pd
df = pd.read_csv('name_of_file.csv', index_col=0)
df.plot(x=df.index, y=df.columns)
Using the CSV that Matti John gave, Namely
使用 Matti John 提供的 CSV，即
a,b,c
20,2,5
40,6,8
60,4,9
This is the output from the code above
这是上面代码的输出
