Question :
I have a dataframe that looks like the following
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
When I do the following:
df.plot(x='x', y='y')
The output is this:
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
Answer #1:
Another simple way is to use the pivot function to format the data as you need first.
df.plot() does the rest
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:
Answer #2:
You could use groupby to split the DataFrame into subgroups according to the color:
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
Answer #3:
If you have seaborn installed, an easier method that does not require you to perform pivot:
import seaborn as sns
sns.lineplot(data=df, x='x', y='y', hue='color')
Answer #4:
You can use this code to get your desire output
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
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
