Python Simple Heat Map

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd

a = np.random.random((5, 4))
df = pd.DataFrame({'a': a[0], 'b': a[1], 'c': a[2], 'd': a[3], 'e': a[4]})
rows = list('abcd')
columns = list(df.columns)

fig = plt.figure(figsize=(10,10), dpi=72) 
ax = fig.add_subplot(111) 
plt.pcolor(df, cmap = plt.cm.Reds) # cmap='hot'

ax.set_xticks(np.arange(0,5)+0.5)
ax.set_yticks(np.arange(0,4)+0.5)
ax.set_yticklabels(rows)
ax.set_xticklabels(columns)
plt.show()