How can I sort the axis in descending order? I tried the following and it did not work:

from io import BytesIO
from fpdf import FPDF
import pandas as pd
import matplotlib.pyplot as plt
import io

DATA = {
    'x': ['val_1', 'val_2', 'val_3', 'val_4', 'val_5'],
    'y': [1, 2, 3, 4, 5]
}

COLUMNS = tuple(DATA.keys())

plt.figure()
df = pd.DataFrame(DATA, columns=COLUMNS)
df.sort_values(['y'], ascending=[False]).plot(x=COLUMNS[0], y=COLUMNS[1], kind="barh", legend=False)

img_buf = BytesIO()
plt.savefig(img_buf, dpi=200)

pdf = FPDF()
pdf.add_page()
pdf.image(img_buf, w=pdf.epw)
pdf.output('output.pdf')
img_buf.close()

How can I sort the axis in descending order? I tried the following and it did not work:

from io import BytesIO
from fpdf import FPDF
import pandas as pd
import matplotlib.pyplot as plt
import io

DATA = {
    'x': ['val_1', 'val_2', 'val_3', 'val_4', 'val_5'],
    'y': [1, 2, 3, 4, 5]
}

COLUMNS = tuple(DATA.keys())

plt.figure()
df = pd.DataFrame(DATA, columns=COLUMNS)
df.sort_values(['y'], ascending=[False]).plot(x=COLUMNS[0], y=COLUMNS[1], kind="barh", legend=False)

img_buf = BytesIO()
plt.savefig(img_buf, dpi=200)

pdf = FPDF()
pdf.add_page()
pdf.image(img_buf, w=pdf.epw)
pdf.output('output.pdf')
img_buf.close()

• python
• pandas
• matplotlib
• fpdf2

2 Answers 2

Or just change ascending = [False] to ascending = [True]:

import pandas as pd
import matplotlib.pyplot as plt

DATA = {
    'x': ['val_1', 'val_2', 'val_3', 'val_4', 'val_5'],
    'y': [1, 2, 3, 2.5, 0.5]
}

COLUMNS = tuple(DATA.keys())


df = pd.DataFrame(DATA, columns=COLUMNS)
df.sort_values(['y'], ascending=[True]).plot(x=COLUMNS[0], y=COLUMNS[1], kind="barh", legend=False)

plt.show()

You can try matplotlib.axes.Axes.invert_yaxis

plt.gca().invert_yaxis()

or for x axis

plt.gca().invert_xaxis()

The code

from io import BytesIO
import pandas as pd
import matplotlib.pyplot as plt

DATA = {
    'x': ['val_1', 'val_2', 'val_3', 'val_4', 'val_5'],
    'y': [1, 2, 3, 4, 5]
}
COLUMNS = tuple(DATA.keys())

plt.figure()
df = pd.DataFrame(DATA, columns=COLUMNS)

df_sorted = df.sort_values(['y'], ascending=[False]).reset_index(drop=True)

df_sorted.plot(x=COLUMNS[0], y=COLUMNS[1], kind="barh", legend=False)

img_buf = BytesIO()
plt.gca().invert_xaxis()

plt.show()

The graph plt.gca().invert_xaxis()

The graph plt.gca().invert_yaxis()