[python] matplotlib을 사용하여 많은 하위 플롯에 대한 단일 범례를 어떻게 만드나요?

여러 서브 플로트의 많은 커브를 참조하는 단일 범례로 이미지를 표시하는 응답이 없으므로 궁금한 점이 있습니다.

이제 코드를보고 싶 습니까?

from numpy import linspace
import matplotlib.pyplot as plt

# Calling the axes.prop_cycle returns an itertoools.cycle

color_cycle = plt.rcParams['axes.prop_cycle']()

# I need some curves to plot

x = linspace(0, 1, 51)
f1 = x*(1-x)   ; lab1 = 'x - x x'
f2 = 0.25-f1   ; lab2 = '1/4 - x + x x'
f3 = x*x*(1-x) ; lab3 = 'x x - x x x'
f4 = 0.25-f3   ; lab4 = '1/4 - x x + x x x'

# let's plot our curves (note the use of color cycle, otherwise the curves colors in
# the two subplots will be repeated and a single legend becomes difficult to read)
fig, (a13, a24) = plt.subplots(2)

a13.plot(x, f1, label=lab1, **next(color_cycle))
a13.plot(x, f3, label=lab3, **next(color_cycle))
a24.plot(x, f2, label=lab2, **next(color_cycle))
a24.plot(x, f4, label=lab4, **next(color_cycle))

# so far so good, now the trick

lines_labels = [ax.get_legend_handles_labels() for ax in fig.axes]
lines, labels = [sum(lol, []) for lol in zip(*lines_labels)]

# finally we invoke the legend (that you probably would like to customize...)

fig.legend(lines, labels)
plt.show()

두 줄

lines_labels = [ax.get_legend_handles_labels() for ax in fig.axes]
lines, labels = [sum(lol, []) for lol in zip(*lines_labels)]

설명 할 가치가 있습니다.이 목표를 위해 함수의 까다로운 부분을 4 줄의 코드로 캡슐화했지만 크게 주석을 달았습니다.

def fig_legend(fig, **kwdargs):

    # generate a sequence of tuples, each contains
    #  - a list of handles (lohand) and
    #  - a list of labels (lolbl)
    tuples_lohand_lolbl = (ax.get_legend_handles_labels() for ax in fig.axes)
    # e.g. a figure with two axes, ax0 with two curves, ax1 with one curve
    # yields:   ([ax0h0, ax0h1], [ax0l0, ax0l1]) and ([ax1h0], [ax1l0])

    # legend needs a list of handles and a list of labels, 
    # so our first step is to transpose our data,
    # generating two tuples of lists of homogeneous stuff(tolohs), i.e
    # we yield ([ax0h0, ax0h1], [ax1h0]) and ([ax0l0, ax0l1], [ax1l0])
    tolohs = zip(*tuples_lohand_lolbl)

    # finally we need to concatenate the individual lists in the two
    # lists of lists: [ax0h0, ax0h1, ax1h0] and [ax0l0, ax0l1, ax1l0]
    # a possible solution is to sum the sublists - we use unpacking
    handles, labels = (sum(list_of_lists, []) for list_of_lists in tolohs)

    # call fig.legend with the keyword arguments, return the legend object

    return fig.legend(handles, labels, **kwdargs)

추신 : 나는 sum(list_of_lists, [])목록의 목록을 평평하게하는 것은 실제로 비효율적 인 방법 이라는 것을 알고 있지만, 나는 목록의 압축을 좋아합니다. 😉

답변

import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec

#Gridspec demo
fig = plt.figure()
fig.set_size_inches(8,9)
fig.set_dpi(100)

rows   = 17 #the larger the number here, the smaller the spacing around the legend
start1 = 0
end1   = int((rows-1)/2)
start2 = end1
end2   = int(rows-1)

gspec = gridspec.GridSpec(ncols=4, nrows=rows)

axes = []
axes.append(fig.add_subplot(gspec[start1:end1,0:2]))
axes.append(fig.add_subplot(gspec[start2:end2,0:2]))
axes.append(fig.add_subplot(gspec[start1:end1,2:4]))
axes.append(fig.add_subplot(gspec[start2:end2,2:4]))
axes.append(fig.add_subplot(gspec[end2,0:4]))

line, = axes[0].plot([0,1],[0,1],'b')           #add some data
axes[-1].legend((line,),('Test',),loc='center') #create legend on bottommost axis
axes[-1].set_axis_off()                         #don't show bottommost axis

fig.tight_layout()
plt.show()

import matplotlib.patches as mpatches
import matplotlib.pyplot as plt
labels = ['Red Bar', 'Magenta Bar', 'Cyan Bar', 'Black Bar']


#####################################
# insert code for the subplots here #
#####################################


# now, create an artist for each color
red_patch = mpatches.Patch(facecolor='r', edgecolor='#000000') #this will create a red bar with black borders, you can leave out edgecolor if you do not want the borders
black_patch = mpatches.Patch(facecolor='k', edgecolor='#000000')
magenta_patch = mpatches.Patch(facecolor='m', edgecolor='#000000')
cyan_patch = mpatches.Patch(facecolor='c', edgecolor='#000000')
fig.legend(handles = [red_patch, magenta_patch, cyan_patch, black_patch],labels=labels,
       loc="center right",
       borderaxespad=0.1)
plt.subplots_adjust(right=0.85) #adjust the subplot to the right for the legend