Seaborn聚类图：subplots_adjust取消颜色条重新定位

Question

我正在尝试使用seaborn制作一个具有侧边色条的热力图。然而，在我的实际应用中，我有很长的列名需要旋转。这需要使用plt.subplots_adjust，否则标签将无法适应图片：

plt.setp(g.ax_heatmap.get_xticklabels(), rotation=90)
plt.subplots_adjust(bottom=0.5)

使用以下简单示例，我发现最后一个命令取消了颜色条的重新定位：

#!/usr/bin/env python3

import seaborn as sns
import matplotlib.pyplot as plt

iris = sns.load_dataset("iris")
species = iris.pop("species")
# Make long column names
iris.columns = ["________".join(label.split("_")) for label in iris.columns]


g = sns.clustermap(iris, col_cluster=False, yticklabels=False)
# Relocate colour bar on the side
g.cax.set_position([.15, .2, .03, .45])
plt.setp(g.ax_heatmap.get_xticklabels(), rotation=90)
plt.savefig("/tmp/unadjusted.png")

plt.cla()

g = sns.clustermap(iris, col_cluster=False, yticklabels=False)
g.cax.set_position([.15, .2, .03, .45])
plt.setp(g.ax_heatmap.get_xticklabels(), rotation=90)
# Adjust to have the column labels not cut out
plt.subplots_adjust(bottom=0.5)
plt.savefig("/tmp/adjusted.png")

这将导致以下图像:

没有 plt.subplots_adjust： 有 plt.subplots_adjust： 为什么会这样?

这是一个 bug 吗?

我该怎么做才能让我的颜色栏在我想要的位置，同时又确保我的旋转颜色标签不会被切断?

- bli

---

subplots_adjust 调整子图位置，正如其名称所示，这是可以预期的。难道你不只是想先调整子图，然后再设置条形图的位置吗？改变命令的顺序应该会得到所需的结果。 - ImportanceOfBeingErnest

谢谢，那很有帮助。不过我必须使用另一种方法来定位颜色条。我会将此作为答案发布。 - bli

Answer 1

根据@ImportanceOfBeingErnest的建议，在移动颜色条之前，我尝试进行了调整。这导致了以下图片:

由于我实际上不需要树状图，只需要聚类结果，因此我可以通过使用树状图框来放置颜色条而获得更好的结果:

#!/usr/bin/env python3

import seaborn as sns
import matplotlib.pyplot as plt

iris = sns.load_dataset("iris")
species = iris.pop("species")
# Make long column names
iris.columns = ["________".join(label.split("_")) for label in iris.columns]

g = sns.clustermap(iris, col_cluster=False, yticklabels=False)
plt.setp(g.ax_heatmap.get_xticklabels(), rotation=90)
# Adjust to have the column labels not cut out
plt.subplots_adjust(bottom=0.5)
g.cax.set_position([.15, .2, .03, .45])
plt.savefig("/tmp/adjusted_before.png")

plt.cla()

g = sns.clustermap(iris, col_cluster=False, yticklabels=False)
plt.setp(g.ax_heatmap.get_xticklabels(), rotation=90)
# Adjust to have the column labels not cut out
plt.subplots_adjust(bottom=0.5)
# Remove the dendrogram (https://dev59.com/2lgQ5IYBdhLWcg3wqFoF#42418968)
g.ax_row_dendrogram.set_visible(False)
# Use the dendrogram box to reposition the colour bar
dendro_box = g.ax_row_dendrogram.get_position()
dendro_box.x0 = (dendro_box.x0 + 2 * dendro_box.x1) / 3
g.cax.set_position(dendro_box)
# Move the ticks to the left (https://dev59.com/KVoU5IYBdhLWcg3w7aGP#36939552)
g.cax.yaxis.set_ticks_position("left")
# If we add a label to the colour bar
# (cbar_kws={"label" : "the_label"} in clustermap arguments)
# we also need to move the label
# g.cax.yaxis.set_label_position("left")
plt.savefig("/tmp/adjusted_before_using_row_dendrogram_box.png")

这将生成以下图片：

---

编辑：使用plt.tight_layout也会出现同样的问题。

在进一步开发我的热力图时，我想要添加带有图例的行颜色（使用此答案中提出的方法）。在我的实际应用中，图例需要足够的水平空间才能从图像中剪切出来。

我想使用plt.tight_layout来调整图像。这又干扰了颜色条的重新定位（甚至没有解决剪切图例的问题...），如下面的示例所示。

#!/usr/bin/env python3

import seaborn as sns
import matplotlib.pyplot as plt

iris = sns.load_dataset("iris")
species = iris.pop("species")
# Make long column names
iris.columns = ["________".join(label.split("_")) for label in iris.columns]


# Associating colours with species
species_list = species.unique()
label_colours = dict(zip(species_list, sns.color_palette("colorblind", len(species_list))))
row_colours = species.map(label_colours)

g = sns.clustermap(iris, col_cluster=False, yticklabels=False, row_colors=row_colours, cbar_kws={"label" : "measure"})
# Adding row colour legend
# https://dev59.com/Cl4c5IYBdhLWcg3wXZcC#27992943
for (label, colour) in label_colours.items():
    # Make long label
    g.ax_col_dendrogram.bar(0, 0, color=colour, label="Iris___________________{}".format(label))
g.ax_col_dendrogram.legend(loc="center", ncol=3)
# Rotating column labels
plt.setp(g.ax_heatmap.get_xticklabels(), rotation=90)
# Adjust to have the column labels not cut out
plt.subplots_adjust(bottom=0.5)
# Remove the dendrogram (https://dev59.com/2lgQ5IYBdhLWcg3wqFoF#42418968)
g.ax_row_dendrogram.set_visible(False)
# Use the dendrogram box to reposition the colour bar
dendro_box = g.ax_row_dendrogram.get_position()
dendro_box.x0 = (dendro_box.x0 + 2 * dendro_box.x1) / 3
g.cax.set_position(dendro_box)
# Move the ticks and labels to the left (https://dev59.com/KVoU5IYBdhLWcg3w7aGP#36939552)
g.cax.yaxis.set_ticks_position("left")
g.cax.yaxis.set_label_position("left")
plt.savefig("/tmp/with_row_colour_lengend.png")

plt.cla()

g = sns.clustermap(iris, col_cluster=False, yticklabels=False, row_colors=row_colours, cbar_kws={"label" : "measure"})
# Adding row colour legend
# https://dev59.com/Cl4c5IYBdhLWcg3wXZcC#27992943
for (label, colour) in label_colours.items():
    # Make long label
    g.ax_col_dendrogram.bar(0, 0, color=colour, label="Iris___________________{}".format(label))
g.ax_col_dendrogram.legend(loc="center", ncol=3)
# Rotating column labels
plt.setp(g.ax_heatmap.get_xticklabels(), rotation=90)
# Adjust to have the column labels not cut out
plt.subplots_adjust(bottom=0.5)
# Remove the dendrogram (https://dev59.com/2lgQ5IYBdhLWcg3wqFoF#42418968)
g.ax_row_dendrogram.set_visible(False)
# Use the dendrogram box to reposition the colour bar
dendro_box = g.ax_row_dendrogram.get_position()
dendro_box.x0 = (dendro_box.x0 + 2 * dendro_box.x1) / 3
g.cax.set_position(dendro_box)
# Move the ticks and labels to the left (https://dev59.com/KVoU5IYBdhLWcg3w7aGP#36939552)
g.cax.yaxis.set_ticks_position("left")
g.cax.yaxis.set_label_position("left")
plt.tight_layout()
plt.savefig("/tmp/tight_after.png")

plt.cla()

g = sns.clustermap(iris, col_cluster=False, yticklabels=False, row_colors=row_colours, cbar_kws={"label" : "measure"})
# Adding row colour legend
# https://dev59.com/Cl4c5IYBdhLWcg3wXZcC#27992943
for (label, colour) in label_colours.items():
    # Make long label
    g.ax_col_dendrogram.bar(0, 0, color=colour, label="Iris___________________{}".format(label))
g.ax_col_dendrogram.legend(loc="center", ncol=3)
plt.tight_layout()
# Rotating column labels
plt.setp(g.ax_heatmap.get_xticklabels(), rotation=90)
# Adjust to have the column labels not cut out
plt.subplots_adjust(bottom=0.5)
# Remove the dendrogram (https://dev59.com/2lgQ5IYBdhLWcg3wqFoF#42418968)
g.ax_row_dendrogram.set_visible(False)
# Use the dendrogram box to reposition the colour bar
dendro_box = g.ax_row_dendrogram.get_position()
dendro_box.x0 = (dendro_box.x0 + 2 * dendro_box.x1) / 3
g.cax.set_position(dendro_box)
# Move the ticks and labels to the left (https://dev59.com/KVoU5IYBdhLWcg3w7aGP#36939552)
g.cax.yaxis.set_ticks_position("left")
g.cax.yaxis.set_label_position("left")
plt.savefig("/tmp/tight_before.png")

这导致以下几个图表：

没有使用plt.tight_layout，右侧的标签被截断 (物种应该是 "virginica"): 在重新定位色条之后调用plt.tight_layout： 在重新定位色条之前调用plt.tight_layout：

- bli