从Pandas DataFrame绘制条形图

Assuming i have a DataFrame that looks like this:

假设我有一个如下所示的DataFrame:

Hour | V1 | V2 | A1 | A2
 0   | 15 | 13 | 25 | 37  
 1   | 26 | 52 | 21 | 45 
 2   | 18 | 45 | 45 | 25 
 3   | 65 | 38 | 98 | 14

Im trying to create a bar plot to compare columns V1 and V2 by the Hour. When I do:

我试图创建一个条形图,按小时比较列V1和V2。当我做:

import matplotlib.pyplot as plt
ax = df.plot(kind='bar', title ="V comp",figsize=(15,10),legend=True, fontsize=12)
ax.set_xlabel("Hour",fontsize=12)
ax.set_ylabel("V",fontsize=12)

I get a plot and a legend with all the columns' values and names. How can I modify my code so the plot and legend only displays the columns V1 and V2

我得到了一个情节和一个包含所有列的值和名称的图例。如何修改我的代码,以便绘图和图例仅显示列V1和V2

1 个解决方案

#1

To plot just a selection of your columns you can select the columns of interest by passing a list to the subscript operator:

要仅绘制列的选择,您可以通过将列表传递给下标运算符来选择感兴趣的列:

ax = df[['V1','V2']].plot(kind='bar', title ="V comp", figsize=(15, 10), legend=True, fontsize=12)

What you tried was df['V1','V2'] this will raise a KeyError as correctly no column exists with that label, although it looks funny at first you have to consider that your are passing a list hence the double square brackets [[]].

您尝试的是df ['V1','V2']这将引发KeyError,因为没有列存在该标签,虽然看起来很有趣,但首先你必须考虑你传递一个列表因此双方括号[ []]。

import matplotlib.pyplot as plt
ax = df[['V1','V2']].plot(kind='bar', title ="V comp", figsize=(15, 10), legend=True, fontsize=12)
ax.set_xlabel("Hour", fontsize=12)
ax.set_ylabel("V", fontsize=12)
plt.show()