Python 用熊猫数据框绘制多条线
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Plotting multiple lines with pandas dataframe
提问by sedavidw
I have a dataframe that looks like the following
我有一个如下所示的数据框
color x y
0 red 0 0
1 red 1 1
2 red 2 2
3 red 3 3
4 red 4 4
5 red 5 5
6 red 6 6
7 red 7 7
8 red 8 8
9 red 9 9
10 blue 0 0
11 blue 1 1
12 blue 2 4
13 blue 3 9
14 blue 4 16
15 blue 5 25
16 blue 6 36
17 blue 7 49
18 blue 8 64
19 blue 9 81
I ultimately want two lines, one blue, one red. The red line should essentially be y=x and the blue line should be y=x^2
我最终想要两条线，一条蓝色，一条红色。红线本质上应该是 y=x，蓝线应该是 y=x^2
When I do the following:
当我执行以下操作时：
df.plot(x='x', y='y')
The output is this:
输出是这样的：
Is there a way to make pandas know that there are two sets? And group them accordingly. I'd like to be able to specify the column 'color' as the set differentiator
有没有办法让熊猫知道有两组？并相应地将它们分组。我希望能够将列“颜色”指定为设置微分器
采纳答案by MrE
Another simple way is to use the pivotfunction to format the data as you need first.
另一种简单的方法是使用该pivot函数首先根据需要格式化数据。
df.plot()does the rest
df.plot()剩下的
df = pd.DataFrame([
['red', 0, 0],
['red', 1, 1],
['red', 2, 2],
['red', 3, 3],
['red', 4, 4],
['red', 5, 5],
['red', 6, 6],
['red', 7, 7],
['red', 8, 8],
['red', 9, 9],
['blue', 0, 0],
['blue', 1, 1],
['blue', 2, 4],
['blue', 3, 9],
['blue', 4, 16],
['blue', 5, 25],
['blue', 6, 36],
['blue', 7, 49],
['blue', 8, 64],
['blue', 9, 81],
], columns=['color', 'x', 'y'])
df = df.pivot(index='x', columns='color', values='y')
df.plot()
pivot effectively turns the data into:
数据透视有效地将数据转换为：
回答by unutbu
You could use groupbyto split the DataFrame into subgroups according to the color:
您可以使用groupby根据颜色将 DataFrame 拆分为子组：
for key, grp in df.groupby(['color']):
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
df = pd.read_table('data', sep='\s+')
fig, ax = plt.subplots()
for key, grp in df.groupby(['color']):
ax = grp.plot(ax=ax, kind='line', x='x', y='y', c=key, label=key)
plt.legend(loc='best')
plt.show()
yields
产量
回答by saimadhu.polamuri
You can use this code to get your desire output
您可以使用此代码来获得您想要的输出
import pandas as pd
import matplotlib.pyplot as plt
df = pd.DataFrame({'color': ['red','red','red','blue','blue','blue'], 'x': [0,1,2,3,4,5],'y': [0,1,2,9,16,25]})
print df
color x y
0 red 0 0
1 red 1 1
2 red 2 2
3 blue 3 9
4 blue 4 16
5 blue 5 25
To plot graph
绘制图形
a = df.iloc[[i for i in xrange(0,len(df)) if df['x'][i]==df['y'][i]]].plot(x='x',y='y',color = 'red')
df.iloc[[i for i in xrange(0,len(df)) if df['y'][i]== df['x'][i]**2]].plot(x='x',y='y',color = 'blue',ax=a)
plt.show()
Output
输出
回答by Cheng
If you have seaborninstalled, an easier method that does not require you to perform pivot:
如果您已经seaborn安装，一个更简单的方法不需要您执行pivot：
import seaborn as sns
sns.lineplot(data=df, x='x', y='y', hue='color')
