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There is a similar question like mine, but I am not satisfied with the answer, because the axis labels there are coordinates, while I am looking to also have the column and index labels written as text as in seaborn.

This is the output of from seaborn which I want to reproduce (never mind the colormap).

Here's the python code I use to generate an output for pgfplots to use.

import pandas as pd
import seaborn as sns
data = [[3, 10], [2, 15]] 
df = pd.DataFrame(data, columns = ['foo', 'bar'],index = ["foo2","bar2"]) 
sns.heatmap(df,annot=True)

def generate_file(df):
 with open("mwe.dat","w") as f:
 for i in range(len(df.index)):
 for j in range(len(df.columns)):
 f.write(" n".format(j,i,df.values[i][j]))
 f.write("n")
generate_file(df)

This create mwe.dat with the following content:

0 0 3
1 0 10

0 1 2
1 1 15

And this is my latex mwe for my current solution, lacking the text labels and the values written in the middle:

documentclass[tikz]standalone
usepackagepgfplots
begindocument

begintikzpicture
 beginaxis[view=090,
 colorbar,
]
 addplot3[matrix plot,point meta=explicit] file mwe.dat;
 endaxis
endtikzpicture

enddocument

This currently outputs this:

So I have two questions:

• how to add text labels to axes, instead of coordinates?


• how to write the value in the middle of the cell?

Since I will be using python anyway to generate the original dataframes, it is okay if I need python to actually generate the entire latex code, but I would prefer a solution, where python only generates a data file containing all info needed for the plot (I want to avoid changing things by hand).

If you change the Python code to also print the column names and index values:

import pandas as pd
import seaborn as sns
data = [[3, 10], [2, 15]] 
df = pd.DataFrame(data, columns = ['foo', 'bar'],index = ["foo2","bar2"]) 
sns.heatmap(df,annot=True)

def generate_file(df):
 with open("mwe.dat","w") as f:
 f.write("x y z xl yln")
 for i,line in enumerate(df.values):
 for j,val in enumerate(line):
 f.write(" n".format(j,i,val, df.columns[j], df.index[j]))
 f.write("n")
generate_file(df)

So mwe.dat becomes

x y z xl yl
0 0 3 foo foo2
1 0 10 bar bar2

0 1 2 foo foo2
1 1 15 bar bar2

Then you can set the tick locations and read the ticklabels from the file like in the code below. x/yticklabels from table seems to assume that the file has a header row, hence the addition of that.

nodes near coords, nodes near coords align=center can be used to place the values in the cells.

Note the use of addplot ... table instead of addplot ... file.

documentclass[border=5mm,tikz]standalone
usepackagepgfplots
begindocument

begintikzpicture
 beginaxis[
 view=090,
 colorbar,
 xtick=data,
 ytick=data,
 xticklabels from table=mwe.datxl,
 yticklabels from table=mwe.datyl,
 yticklabel style=rotate=90
]
 addplot3[matrix plot, nodes near coords, nodes near coords align=center] table mwe.dat;
 endaxis
endtikzpicture

enddocument

Here's one way

documentclass[tikz,border=20pt]standalone
usepackagepgfplots, filecontents
pgfplotssetcompat=1.13
begindocument
beginfilecontents*mwe.dat
0 0 3
1 0 10

0 1 2
1 1 15
endfilecontents*
begintikzpicture
 beginaxis[view=090, colorbar,hide axis,nodes near coords = pgfmathprintnumberpgfplotspointmeta]
 addplot [matrix plot*,point meta=explicit] file mwe.dat;
 node[] at (axis cs: -0.010,-.65) foo;
 node[] at (axis cs: 0.980,-.65) bar;
 node[rotate=90] at (axis cs: -0.59,.01) bar2;
 node[rotate=90] at (axis cs: -0.590,1.0) foo2;
 endaxis
endtikzpicture
enddocument

The output from Gummi is:

With respect to your question "how to add text labels to axes, instead of coordinates?" I did hide axis in setting the axis. Then I added nodes with the labels you wanted and positioned them and rotated them where you wanted. As for "how to write the value in the middle of the cell?", I added nodes near coords = pgfmathprintnumberpgfplotspointmeta in setting up the axis. I'm wondering about the data file matching up with your picture, though, as the numbers are in the wrong row. The colors are in different rows as well.