python - Keeping some ticks in Seaborn heatmap plot

Question

I have this data frame:

Position    FLK
75.38   1.653608512
75.45   2.404366644
75.47   4.281285701
75.48   5.457803236
75.56   4.281285701
75.61   3.348777004
75.63   5.457803236
75.67   4.281285701
75.70   2.863168526
75.74   2.404366644
75.75   2.863168526
75.78   2.863168526
75.93   3.348777004
75.96   2.863168526
75.99   2.863168526
76.07   0.167253206
76.11   2.863168526
76.14   2.863168526

I used this script for heatmap plotting in Seaborn:

import matplotlib.pyplot as plt
import pandas as pd
import seaborn as sns
import numpy as np
df = pd.read_csv("D.txt",delimiter=r"s+",header=0)
df.set_index('Position')
FLK=(df[['FLK']]).T
sns.heatmap(FLK)
plt.show()

and then get this figure:

I want to know how can I keep some x-ticks (0,2,3,4,5,6,12,15) in this plot, like this:

Answer 1

You can use plt.ticks to select certain tick positions. The way this heatmap is created, generates x ticks with text labels with names '0', '1', '2', ... at positions 0.5, 1.5, 2.5, .... . Therefore, you can select some of the ticks via plt.xticks(np.array([0, 2, 3, 4, 5, 6, 12, 15]) + 0.5).

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

df = pd.DataFrame({'FLK': np.random.uniform(0, 5, 18)})
FLK = (df[['FLK']]).T
sns.heatmap(FLK)
plt.xticks(np.array([0, 2, 3, 4, 5, 6, 12, 15]) + 0.5)
plt.tight_layout()
plt.show()

PS: Note that df.set_index('Position') either needs to be assigned again to df or needs the parameter inplace=True to have some effect. In that case, the labels would be these indices, for which you can select a subset with the same plt.xticks(np.array([0, 2, 3, 4, 5, 6, 12, 15]) + 0.5).