plt.figure(figsize=(7, 7), dpi=300)
groups = [[1.04, 0.96], [1.69, 4.02]]
group_labels = ['G1', 'G2']
num_items = len(group_labels)
ind = np.arange(num_items)
margin = 0.05
width = (1.0 - 2.0 * margin) / num_items
s = plt.subplot(1, 1, 1)
for num, vals in enumerate(groups):
    print('plotting: ', vals)
xdata = ind + margin + num * width
gene_rects = plt.bar(xdata, vals, width)
s.set_xticks(ind + 0.5)
s.set_xticklabels(group_labels)
установка интервала между сгруппированными гистограммами в matplotlib