matplotlib: using a colormap to color table-cell background

Question

I have a Pandas dataframe, and i want to plot it as matplotlib table. So far i have that part working with following code: ``` import numpy as np randn = np.random.randn from pandas import * idx = Index(arange(1,11)) df = DataFrame(randn(10, 5), index=idx, columns=['A', 'B', 'C', 'D', 'E']) vals = np.around(df.values,2) fig = plt.figure(figsize=(15,8)) ax = fig.add_subplot(111, frameon=True, xticks=[], yticks=[]) the_table=plt.table(cellText=vals, rowLabels=df.index, colLabels=df.columns, colWidths = [0.03]*vals.shape[1], loc='center') table_props = the_table.properties() table_cells = table_props['child_artists'] clm = cm.hot(vals) for cell in table_cells: cell.set_height(0.04) # now i would like to set the backgroundcolor of the cell ``` At the end of this i would like to set the background-color of the cell according to the colormap - but how do i look it up in the clm array without an index? Another question: can i somehow pass a format string to the table, so that it formats the…

Accepted Answer

You can use `plt.Normalize()` to normalize your data, and the pass the normalized data to a `Colormap` object, for example `plt.cm.hot()`.

`plt.table()` has an argument `cellColours`, which will be used to set the cells' background color accordingly.

Because `cm.hot` maps black to the minimal value, I increased the value range when creating the normalization object.

Here is the code:

```
from matplotlib import pyplot as plt
import numpy as np
randn = np.random.randn
from pandas import *

idx = Index(np.arange(1,11))
df = DataFrame(randn(10, 5), index=idx, columns=['A', 'B', 'C', 'D', 'E'])
vals = np.around(df.values,2)
norm = plt.Normalize(vals.min()-1, vals.max()+1)
colours = plt.cm.hot(normal(vals))

fig = plt.figure(figsize=(15,8))
ax = fig.add_subplot(111, frameon=True, xticks=[], yticks=[])

the_table=plt.table(cellText=vals, rowLabels=df.index, colLabels=df.columns, 
                    colWidths = [0.03]*vals.shape[1], loc='center', 
                    cellColours=colours)
plt.show()
```

matplotlib: using a colormap to color table-cell background

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