CODEWITHSUNDEEP
pythonpandasseaborn
The Nightman
The Nightman

Reputation: 5759

Combining multiple seaborn heatmaps together

My DataFrame:

    A   B   Up  Down    p
0   1   x   A   A   0.5
1   1   x   T   T   0.5
2   1   y   G   G   0.5
3   1   y   C   C   0.5
4   2   x   A   A   0.5
5   2   x   T   T   0.5
6   2   y   G   G   0.5
7   2   y   C   C   0.5

Code:

pd.DataFrame(
    {'A': {0: 1,1: 1,2: 1,3: 1,4: 2,5: 2,6: 2,7: 2},
     'B': {0: 'x',1: 'x',2: 'y',3: 'y',4: 'x',5: 'x',6: 'y',7: 'y'},
     'Up': {0: 'A', 1: 'T', 2: 'G', 3: 'C', 4: 'A', 5: 'T', 6: 'G', 7: 'C'},
     'Down': {0: 'A', 1: 'T', 2: 'G', 3: 'C', 4: 'A', 5: 'T', 6: 'G', 7: 'C'},
     'p': {0: 0.5,1: 0.5,2: 0.5,3: 0.5,4: 0.5,5: 0.5,6: 0.5,7: 0.5}})

I am trying to use seaborn to plot out a heatmap of the above dataset. I can generate individual heatplots by manually looping through unique combinations of columns A and B but I would like to have them all in the same plot as sns.FacetGrid enables.

I would like to generate individual heatplots for each combination of columns A and B. Each of those heatplots should use Up as the y-axis and Down as the x-axis. Values for each square within the heatplots should use column p.

I would also like to be able to control the coloration for the range of p values. The way I'm currently doing this is with something like the following:

from matplotlib.colors import LogNorm
lognorm = LogNorm(vmin=1.0 / (10.0 ** 200), vmax=1.0)
ax = sns.heatmap(df, norm = lognorm,)

Upvotes: 0

Views: 312

Answers (1)

JohanC
JohanC

Reputation: 80309

You could create a FacetGrid with 'A' and 'B' for rows and columns. Then the axes_dict of that FacetGrid will contain a subplot (ax) for each combination of 'A' and 'B'. These 'A' and 'B' can be used to take a subset of the dataframe as input for a pivot table.

g = sns.FacetGrid(df, row='A', col='B')
lognorm = LogNorm(vmin=1.0 / (10.0 ** 200), vmax=1.0)
for (a, b), ax in g.axes_dict.items():
    sns.heatmap(df[(df['A'] == a) & (df['B'] == b)].pivot('Up', 'Down', 'p'), norm=lognorm, ax=ax)
    ax.set_title(f'A={a} B={b}')

Upvotes: 2

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