[FIXED] Change "Q" quarterly data to custom "kv" in Matplotlib timeline chart on x axis Python

Issue

I have done the following timeline chart in Python. Where the data is in quarterly format by datetimeindex. However, I need to translate the graph into my local language and therefore replace "Q1", "Q2", "Q3", "Q4" with "kv1", "kv2", "kv3", "kv4". Is this possible? So I need the x axsis to be kv3, kv4, kv1 2022, kv2 instead of Q3, Q4, Q1 2022, Q2 and so fourth.

import random
import numpy as np
import matplotlib
import matplotlib.pyplot as plt
from matplotlib.pyplot import figure
import pandas
plt.style.use('seaborn-whitegrid')
matplotlib.rcParams['font.sans-serif'] = "Arial"
matplotlib.rcParams['font.family'] = "Arial"

categories = ['Car','Train','Boat', 'Plane', 'Walk' ]

cat_dict = dict(zip(categories, range(1, len(categories)+1)))

val_dict = dict(zip(range(1, len(categories)+1), categories))

dates = pandas.DatetimeIndex(freq='Q', start='2021-09-30', end='2023-12-31')
values = [random.choice(categories) for _ in range(len(dates))]
df = pandas.DataFrame(data=values, index=dates, columns=['category'])

df['plotval'] = [float('NaN'),1,1,3,1,float('NaN'),5,2,1,float('NaN')]
df['plotval'][0] = np.nan

plt.rcParams["figure.figsize"] = 4,3.5
plt.figure(dpi=1000)
fig, ax = plt.subplots()

df['plotval'].plot(ax=ax, style='^',color='darkblue', label = "Renteheving", markersize=12)

ax.margins(0.2)
ax.spines['top'].set_visible(False)
ax.yaxis.set_major_formatter(plt.FuncFormatter(lambda x, pos: val_dict.get(x)))
plt.yticks( weight = 'bold')

I tried to add

plt.xlabel(["kv1", "kv2", "kv3", "kv4"])

Which gave me

Help is as always highly appreciated.

Solution

Try to add this to your code:

# Call draw to populate tick labels
plt.draw()

# Change major labels
new_major_labels = []
for label in ax.get_xticklabels(minor=False):
    s = label.get_text()
    label.set_text(s.replace('Q', 'kv'))
    new_major_labels.append(label)
    
ax.set_xticklabels(new_major_labels, minor=False)

# Change minor labels
new_minor_labels = []
for label in ax.get_xticklabels(minor=True):
    s = label.get_text()
    label.set_text(s.replace('Q', 'kv'))
    new_minor_labels.append(label)
    
ax.set_xticklabels(new_minor_labels, minor=True)

It throws a warning which I don't understand, but I think it does what you want.

Answered By - Simone