python - plotnine - 在同一个图中有两个图并打印它的任何解决方法

Question

我使用 plotnine 做了两个图在 python 中。我知道并不真正支持绘制子图( here )。我想知道是否有办法解决并在一个图中创建子图。

我想用 plotineplot.draw() 把它们做成图然后用 matplotlib 读取或先将它们保存为 png，然后用 matplotlib 读取它们并将它们放在一起。但是，我对 matplotlib 不是很方便，到现在为止的每一次尝试都是徒劳的。

示例 plotnine 图:

from plotnine import data
from plotnine import *

plot1 = (ggplot(data.mtcars, aes('wt', 'mpg', color='factor(gear)'))
 + geom_point()
 + stat_smooth(method='lm')
 + facet_wrap('~gear'))

任何帮助都会非常有帮助。

Answer 1

最终我创建了一个解决方法，将绘图保存为图像，然后再次加载它们并组合它们。这不是最快或最有效的方式，但效果很好。

import plotnine as gg
import matplotlib.pyplot as plt
import matplotlib.image as img
import os
import numpy as np

def _check_plotnine_grid(plots_list, figsize):
    if not type(plots_list) == list:
        raise ValueError('Input plots_list is not a list')
    if (not type(figsize) == tuple) or (not len(figsize) == 2):
        raise ValueError('Input figsize should be a tuple of length 2')


def plotnine_grid(plots_list, row=None, col=1, height=None, width=None, dpi=500, ratio=None, pixels=10000,
                  figsize=(12, 8)):

"""
Create a grid of plotnine plots.


Function input
----------
plots_list      : a list of plotnine.ggplots
row, col        : numerics to indicate in how many rows and columns the plots should be ordered in the grid
              defaults: row -> length of plots_list; col -> 1
height, width   : the height and width of the individual subplots created by plotnine
                can be automatically determined by a combination of dpi, ratio and pixels
dpi             : the density of pixels in the image. Default: 500. Higher numbers could lead to crisper output,
                depending on exact situation
ratio           : the ratio of heigth to width in the output. Standard value is 1.5 x col/row.
                Not used if height & width are given.
pixels          : the total number of pixels used, default 10000. Not used if height & width are given.
figsize         : tuple containing the size of the final output after making a grid, in pixels (default: (1200,800))



Function output
----------
A matplotlib figure that can be directly saved with output.savefig().
"""

    _check_plotnine_grid(plots_list, figsize)  # Check the input

    # Assign values that have not been provided based on others. In the end, height and width should be provided.
    if row is None:
    row = len(plots_list)

    if ratio is None:
    ratio = 1.5 * col / row

    if height is None and width is not None:
    height = ratio * width

    if height is not None and width is None:
    width = height / ratio

    if height is None and width is None:
    area = pixels / dpi
    width = np.sqrt(area/ratio)
    height = ratio * width

    # Do actual subplot creation and plot output.
    i = 1
    fig = plt.figure(figsize=figsize)
    plt.autoscale(tight=True)
    for image_sel in plots_list:  # image_sel = plots_list[i]
    image_sel.save('image' + str(i) + '.png', height=height, width=width, dpi=500, verbose=False)
    fig.add_subplot(row, col, i)
    plt.imshow(img.imread('image' + str(i) + '.png'), aspect='auto')
    fig.tight_layout()
    fig.get_axes()[i-1].axis('off')
    i = i + 1
    os.unlink('image' + str(i - 1) + '.png')  # os.unlink is basically os.remove but in some cases quicker
    fig.patch.set_visible(False)
    return fig