Python / Matplotlib - 有没有办法制作不连续的轴？

Question

我正在尝试使用具有不连续x轴的pyplot创建绘图。绘制的通常方法是轴将具有如下内容：

（值）---- // ----（后来的值）

其中//表示您正在跳过（值）和（后面的值）之间的所有内容。

我无法找到任何这方面的例子，所以我想知道它是否可能。我知道你可以通过不连续性加入数据，例如财务数据，但我想让轴上的跳转更明确。目前我只是使用子图，但我真的希望最终在同一个图上最终得到所有内容。

Answer 1

保罗的回答是一个非常好的方法。

但是，如果您不想进行自定义转换，则可以使用两个子图来创建相同的效果。

而不是从头开始组合一个例子，在matplotlib示例中有an excellent example of this written by Paul Ivanov（它仅在当前的git提示中，因为它仅在几个月前提交。它还没有出现在网页上。）。

这只是对此示例的一个简单修改，即具有不连续的x轴而不是y轴。 （这就是我将这篇文章改为CW的原因）

基本上，你只需要这样做：

import matplotlib.pylab as plt
import numpy as np

# If you're not familiar with np.r_, don't worry too much about this. It's just 
# a series with points from 0 to 1 spaced at 0.1, and 9 to 10 with the same spacing.
x = np.r_[0:1:0.1, 9:10:0.1]
y = np.sin(x)

fig,(ax,ax2) = plt.subplots(1, 2, sharey=True)

# plot the same data on both axes
ax.plot(x, y, 'bo')
ax2.plot(x, y, 'bo')

# zoom-in / limit the view to different portions of the data
ax.set_xlim(0,1) # most of the data
ax2.set_xlim(9,10) # outliers only

# hide the spines between ax and ax2
ax.spines['right'].set_visible(False)
ax2.spines['left'].set_visible(False)
ax.yaxis.tick_left()
ax.tick_params(labeltop='off') # don't put tick labels at the top
ax2.yaxis.tick_right()

# Make the spacing between the two axes a bit smaller
plt.subplots_adjust(wspace=0.15)

plt.show()

要添加断轴线//效果，我们可以这样做（再次，从Paul Ivanov的例子中修改）：

import matplotlib.pylab as plt
import numpy as np

# If you're not familiar with np.r_, don't worry too much about this. It's just 
# a series with points from 0 to 1 spaced at 0.1, and 9 to 10 with the same spacing.
x = np.r_[0:1:0.1, 9:10:0.1]
y = np.sin(x)

fig,(ax,ax2) = plt.subplots(1, 2, sharey=True)

# plot the same data on both axes
ax.plot(x, y, 'bo')
ax2.plot(x, y, 'bo')

# zoom-in / limit the view to different portions of the data
ax.set_xlim(0,1) # most of the data
ax2.set_xlim(9,10) # outliers only

# hide the spines between ax and ax2
ax.spines['right'].set_visible(False)
ax2.spines['left'].set_visible(False)
ax.yaxis.tick_left()
ax.tick_params(labeltop='off') # don't put tick labels at the top
ax2.yaxis.tick_right()

# Make the spacing between the two axes a bit smaller
plt.subplots_adjust(wspace=0.15)

# This looks pretty good, and was fairly painless, but you can get that
# cut-out diagonal lines look with just a bit more work. The important
# thing to know here is that in axes coordinates, which are always
# between 0-1, spine endpoints are at these locations (0,0), (0,1),
# (1,0), and (1,1). Thus, we just need to put the diagonals in the
# appropriate corners of each of our axes, and so long as we use the
# right transform and disable clipping.

d = .015 # how big to make the diagonal lines in axes coordinates
# arguments to pass plot, just so we don't keep repeating them
kwargs = dict(transform=ax.transAxes, color='k', clip_on=False)
ax.plot((1-d,1+d),(-d,+d), **kwargs) # top-left diagonal
ax.plot((1-d,1+d),(1-d,1+d), **kwargs) # bottom-left diagonal

kwargs.update(transform=ax2.transAxes) # switch to the bottom axes
ax2.plot((-d,d),(-d,+d), **kwargs) # top-right diagonal
ax2.plot((-d,d),(1-d,1+d), **kwargs) # bottom-right diagonal

# What's cool about this is that now if we vary the distance between
# ax and ax2 via f.subplots_adjust(hspace=...) or plt.subplot_tool(),
# the diagonal lines will move accordingly, and stay right at the tips
# of the spines they are 'breaking'

plt.show()

Answer 2

我看到很多关于此功能的建议，但没有迹象表明它已经实现。这是一个可行的解决方案。它将步进函数变换应用于x轴。这是很多代码，但它相当简单，因为它大部分是样板自定义比例的东西。我没有添加任何图形来指示休息的位置，因为这是一个风格问题。祝你好运完成工作。

from matplotlib import pyplot as plt
from matplotlib import scale as mscale
from matplotlib import transforms as mtransforms
import numpy as np

def CustomScaleFactory(l, u):
    class CustomScale(mscale.ScaleBase):
        name = 'custom'

        def __init__(self, axis, **kwargs):
            mscale.ScaleBase.__init__(self)
            self.thresh = None #thresh

        def get_transform(self):
            return self.CustomTransform(self.thresh)

        def set_default_locators_and_formatters(self, axis):
            pass

        class CustomTransform(mtransforms.Transform):
            input_dims = 1
            output_dims = 1
            is_separable = True
            lower = l
            upper = u
            def __init__(self, thresh):
                mtransforms.Transform.__init__(self)
                self.thresh = thresh

            def transform(self, a):
                aa = a.copy()
                aa[a>self.lower] = a[a>self.lower]-(self.upper-self.lower)
                aa[(a>self.lower)&(a<self.upper)] = self.lower
                return aa

            def inverted(self):
                return CustomScale.InvertedCustomTransform(self.thresh)

        class InvertedCustomTransform(mtransforms.Transform):
            input_dims = 1
            output_dims = 1
            is_separable = True
            lower = l
            upper = u

            def __init__(self, thresh):
                mtransforms.Transform.__init__(self)
                self.thresh = thresh

            def transform(self, a):
                aa = a.copy()
                aa[a>self.lower] = a[a>self.lower]+(self.upper-self.lower)
                return aa

            def inverted(self):
                return CustomScale.CustomTransform(self.thresh)

    return CustomScale

mscale.register_scale(CustomScaleFactory(1.12, 8.88))

x = np.concatenate((np.linspace(0,1,10), np.linspace(9,10,10)))
xticks = np.concatenate((np.linspace(0,1,6), np.linspace(9,10,6)))
y = np.sin(x)
plt.plot(x, y, '.')
ax = plt.gca()
ax.set_xscale('custom')
ax.set_xticks(xticks)
plt.show()

Answer 3

检查brokenaxes包：

import matplotlib.pyplot as plt
from brokenaxes import brokenaxes
import numpy as np

fig = plt.figure(figsize=(5,2))
bax = brokenaxes(xlims=((0, .1), (.4, .7)), ylims=((-1, .7), (.79, 1)), hspace=.05)
x = np.linspace(0, 1, 100)
bax.plot(x, np.sin(10 * x), label='sin')
bax.plot(x, np.cos(10 * x), label='cos')
bax.legend(loc=3)
bax.set_xlabel('time')
bax.set_ylabel('value')

Answer 4

当使用比率不等于1：1的格子规格时，如果使用Frederick Nord的问题如何启用对角线“断裂”线的平行方向，基于Paul Ivanov和Joe Kingtons的提议进行的以下更改可能会有所帮助。宽度比可以使用变量n和m来改变。

import matplotlib.pylab as plt
import numpy as np
import matplotlib.gridspec as gridspec

x = np.r_[0:1:0.1, 9:10:0.1]
y = np.sin(x)

n = 5; m = 1;
gs = gridspec.GridSpec(1,2, width_ratios = [n,m])

plt.figure(figsize=(10,8))

ax = plt.subplot(gs[0,0])
ax2 = plt.subplot(gs[0,1], sharey = ax)
plt.setp(ax2.get_yticklabels(), visible=False)
plt.subplots_adjust(wspace = 0.1)

ax.plot(x, y, 'bo')
ax2.plot(x, y, 'bo')

ax.set_xlim(0,1)
ax2.set_xlim(10,8)

# hide the spines between ax and ax2
ax.spines['right'].set_visible(False)
ax2.spines['left'].set_visible(False)
ax.yaxis.tick_left()
ax.tick_params(labeltop='off') # don't put tick labels at the top
ax2.yaxis.tick_right()

d = .015 # how big to make the diagonal lines in axes coordinates
# arguments to pass plot, just so we don't keep repeating them
kwargs = dict(transform=ax.transAxes, color='k', clip_on=False)

on = (n+m)/n; om = (n+m)/m;
ax.plot((1-d*on,1+d*on),(-d,d), **kwargs) # bottom-left diagonal
ax.plot((1-d*on,1+d*on),(1-d,1+d), **kwargs) # top-left diagonal
kwargs.update(transform=ax2.transAxes) # switch to the bottom axes
ax2.plot((-d*om,d*om),(-d,d), **kwargs) # bottom-right diagonal
ax2.plot((-d*om,d*om),(1-d,1+d), **kwargs) # top-right diagonal

plt.show()

Answer 5

对于那些感兴趣的人，我扩展了@Paul的答案并将其添加到ProPlot matplotlib package中。它可以做轴"jumps", "speedups", and "slowdowns"。

目前尚无办法像Joe的回答那样添加表示离散跳跃的“叉号”，但我计划在将来添加。我还计划添加一个默认的“ tick locator”，以根据CutoffScale参数设置合理的默认tick位置。

Answer 6

一个非常简单的技巧是

1. 轴脊上的散点图矩形和
2. 在该位置绘制“//”作为文本。

对我来说就像一个魅力：

# FAKE BROKEN AXES
# plot a white rectangle on the x-axis-spine to "break" it
xpos = 10 # x position of the "break"
ypos = plt.gca().get_ylim()[0] # y position of the "break"
plt.scatter(xpos, ypos, color='white', marker='s', s=80, clip_on=False, zorder=100)
# draw "//" on the same place as text
plt.text(xpos, ymin-0.125, r'//', fontsize=label_size, zorder=101, horizontalalignment='center', verticalalignment='center')

示例情节：