Plotting Pandas dataframe subplots with different linestyles - pandas

Question

I am plotting a figure with 6 sets of axes, each with a series of 3 lines from one of 2 Pandas dataframes (1 line per column).
I have been using matplotlib .plot:
import pandas as pd
import matplotlib.pyplot as plt
idx = pd.DatetimeIndex(start = '2013-01-01 00:00', periods =24,freq = 'H')
df1 = pd.DataFrame(index = idx, columns = ['line1','line2','line3'])
df1['line1']= df1.index.hour
df1['line2'] = 24 - df1['line1']
df1['line3'] = df1['line1'].mean()
df2 = df1*2
df3= df1/2
df4= df2+df3
fig, ax = plt.subplots(2,2,squeeze=False,figsize = (10,10))
ax[0,0].plot(df1.index, df1, marker='', linewidth=1, alpha=1)
ax[0,1].plot(df2.index, df2, marker='', linewidth=1, alpha=1)
ax[1,0].plot(df3.index, df3, marker='', linewidth=1, alpha=1)
ax[1,1].plot(df4.index, df4, marker='', linewidth=1, alpha=1)
fig.show()
It's all good, and matplotlib automatically cycles through a different colour for each line, but uses the same colours for each plot, which is what i wanted.
However, now I want to specify more details for the lines: choosing specific colours for each line, and / or changing the linestyle for each line.
This link shows how to pass multiple linestyles to a Pandas plot. e.g. using
ax = df.plot(kind='line', style=['-', '--', '-.'])
So I need to either:
pass lists of styles to my subplot command above, but style is not recognised and it doesn't accept a list for linestyle or color. Is there a way to do this?
or
Use df.plot:
fig, ax = plt.subplots(2,2,squeeze=False,figsize = (10,10))
ax[0,0] = df1.plot(style=['-','--','-.'], marker='', linewidth=1, alpha=1)
ax[0,1] = df2.plot(style=['-','--','-.'],marker='', linewidth=1, alpha=1)
ax[1,0] = df3.plot( style=['-','--','-.'],marker='', linewidth=1, alpha=1)
ax[1,1] = df4.plot(style=['-','--','-.'], marker='', linewidth=1, alpha=1)
fig.show()
...but then each plot is plotted as a seperate figure. I can't see how to put multiple Pandas plots on the same figure.
How can I make either of these approaches work?

Answer 1

using matplotlib
Using matplotlib, you may define a cycler for the axes to loop over color and linestyle automatically. (See this answer).
import numpy as np; np.random.seed(1)
import pandas as pd
import matplotlib.pyplot as plt
f = lambda i: pd.DataFrame(np.cumsum(np.random.randn(20,3),0))
dic1= dict(zip(range(3), [f(i) for i in range(3)]))
dic2= dict(zip(range(3), [f(i) for i in range(3)]))
dics = [dic1,dic2]
rows = range(3)
def set_cycler(ax):
ax.set_prop_cycle(plt.cycler('color', ['limegreen', '#bc15b0', 'indigo'])+
plt.cycler('linestyle', ["-","--","-."]))
fig, ax = plt.subplots(3,2,squeeze=False,figsize = (8,5))
for x in rows:
for i,dic in enumerate(dics):
set_cycler(ax[x,i])
ax[x,i].plot(dic[x].index, dic[x], marker='', linewidth=1, alpha=1)
plt.show()
using pandas
Using pandas you can indeed supply a list of possible colors and linestyles to the df.plot() method. Additionally you need to tell it in which axes to plot (df.plot(ax=ax[i,j])).
import numpy as np; np.random.seed(1)
import pandas as pd
import matplotlib.pyplot as plt
f = lambda i: pd.DataFrame(np.cumsum(np.random.randn(20,3),0))
dic1= dict(zip(range(3), [f(i) for i in range(3)]))
dic2= dict(zip(range(3), [f(i) for i in range(3)]))
dics = [dic1,dic2]
rows = range(3)
color = ['limegreen', '#bc15b0', 'indigo']
linestyle = ["-","--","-."]
fig, ax = plt.subplots(3,2,squeeze=False,figsize = (8,5))
for x in rows:
for i,dic in enumerate(dics):
dic[x].plot(ax=ax[x,i], style=linestyle, color=color, legend=False)
plt.show()