How can I rotate column titles in pyplot.table?

问题

I'm creating a table in matplotlib, but the table headers are long strings, and the table values are numbers with only a few digits. This leaves me with two bad options: either my table is much wider than necessary, or my headers overlap. To fix this, I'd like to rotate the table headings (possibly up to 90 degrees). In other words, I want to do this in python

Here's my simplified code right now:

import matplotlib, numpy
import matplotlib.pyplot as plt

data=numpy.array([[1, 2],[3,4]])
headings=['long heading 1', 'long heading 2']
fig=plt.figure(figsize=(5,2))
ax=fig.add_subplot(111, frameon=False, xticks=[], yticks=[])

the_table = plt.table(cellText=data, rowLabels=headings, colLabels=headings, colWidths=[0.3]*data.shape[1], loc='center') #0.3 for second image, 0.03 for first
#the_table.auto_set_font_size(False) #comment out for second image
#the_table.set_fontsize(10) #comment out for second image
the_table.scale(1, 1.6)
plt.show()

This produces either the squished image, or the super-wide image (both shown below). In my actual code, the table is ~30 x 30, so the cells can't be very wide. Does anybody know how to rotate the column titles to fix this spacing issue?

回答1:

I figured it out. It's not pretty, but it works. I added two annotations for each column - the text, and a line to separate it from the next column header. I had to define some parameters that apply to the table and the fancy labels (width, height, col_width), and some parameters to make the fancy labels line up correctly. This solution worked fine on my 30x30 table.

import matplotlib, numpy
import matplotlib.pyplot as plt

width=5
height=3
col_width=.075

data=numpy.array([[1, 2,5],[3,4,7],[7,9,5]])
headings=['long heading 1', 'long heading 2', 'longish 3']
fig=plt.figure(figsize=(width,height))
ax=fig.add_subplot(111, frameon=False, xticks=[], yticks=[])

the_table = plt.table(cellText=data, rowLabels=headings, 
    colWidths=[col_width]*data.shape[1], loc='center') #remove colLabels
the_table.auto_set_font_size(False) 
the_table.set_fontsize(10) 
the_table.scale(1, 1.6)

#custom heading titles - new portion
hoffset=0.42 #find this number from trial and error
voffset=0.66 #find this number from trial and error
line_fac=0.98 #controls the length of the dividing line
count=0
for string in headings:
    ax.annotate('  '+string, xy=(hoffset+count*col_width,voffset),
        xycoords='axes fraction', ha='left', va='bottom', 
        rotation=45, size=10)

    #add a dividing line
    ax.annotate('', xy=(hoffset+(count+0.5)*col_width,voffset), 
        xytext=(hoffset+(count+0.5)*col_width+line_fac/width,voffset+line_fac/height),
        xycoords='axes fraction', arrowprops={'arrowstyle':'-'})

    count+=1

plt.show()

回答2:

I just found an other solution:

for cell in table._cells:
    if cell[0] ==0:
        table._cells[cell].get_text().set_rotation(90)

The first loop is for going through all cells, the second is for picking the first row/header.

if cell[1] =- -1

this would selecte the the first column, which you might want to rotate, too.

Then you can rotate the cell text by e.g. 90 °.

来源：https://stackoverflow.com/questions/35003603/how-can-i-rotate-column-titles-in-pyplot-table

标签

python

matplotlib