CODEWITHSUNDEEP
pythonmatplotlib
Thomas Coll
Thomas Coll

Reputation: 25

Python - MatPlotLib - How can I set two ticks on my x axis, one at the far left and one at the far right?

So I am trying to display some analytics in my python web-app. I want to display the date-time for the first and last entries on the x axis.

I have attempted to set the ticks as a two entry list but it gave a bad result.

plt.scatter(x_data, y_data)
    plt.grid(True)
    plt.xticks(x_data, [x_data[0], x_data[-1]])
    fig = plt.gcf()

Where the x_data is:

['10:59:44 27-03-2019', '11:00:07 27-03-2019', '11:00:09 27-03-2019', '11:00:12 27-03-2019', '11:30:23 27-03-2019', '11:30:29 27-03-2019', '11:30:30 27-03-2019', '11:30:31 27-03-2019', '11:30:32 27-03-2019', '11:32:44 27-03-2019', '11:33:21 27-03-2019', '11:35:50 27-03-2019', '12:16:12 27-03-2019', '12:16:39 27-03-2019', '12:17:36 27-03-2019', '12:19:40 27-03-2019', '12:23:50 27-03-2019']

I expected the output to place one on the far left and the other on the far right. Instead the first two ticks simply showed the times overlapping.

I am unsure what the proper way of doing it is.

Upvotes: 2

Views: 535

Answers (2)

CAPSLOCK
CAPSLOCK

Reputation: 6483

I suspect your problem is that you are defining a vector of ticks and then assigning two labels (in position 0 and 1).

import numpy as np
import matplotlib.pyplot as plt

x_data=np.array([1,2,3,4,5,6,7,8])
y_data=np.random.normal(0, 1, (8, 1))

# create an array for your labels 
new_labels=[''] * (len(x_data)-2)
new_labels.insert(0,x_data[0])
new_labels.append(x_data[-1])

plt.scatter(x_data, y_data)
plt.grid(True)
plt.xticks(x_data, new_labels) #use the new tick labels
fig = plt.gcf()

Upvotes: 1

Sheldore
Sheldore

Reputation: 39042

Here is a workaround solution using some random data because you did not specify what the y_data is. The idea is to loop through the existing default tick labels and then replace all the tick labels by empty strings except the first and the last one.

fig, ax = plt.subplots()

plt.scatter(x_data, range(len(x_data)))
plt.grid(True)

fig.canvas.draw()
xticks = ax.get_xticklabels()
labels_new = [lab.get_text() if i in [0, len(xticks)-1] else "" 
          for i, lab in enumerate(xticks) ]

ax.set_xticklabels(labels_new)

plt.show()

enter image description here

Upvotes: 2

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