CODEWITHSUNDEEP
pythonmatplotlibnumeric
Shan
Shan

Reputation: 19243

how to visualize values on logarithmic scale on matplotalib?

I have vales with very small difference like... 0.000001. I want to visualize them on logarithmic scale. I am wondering how to do it in matplotlib.

Thanks a lot

Upvotes: 7

Views: 36192

Answers (4)

bluenote10
bluenote10

Reputation: 26530

Since all other answers only mention the global pyplot.xscale("log") approach: You can also set it per axis, but then the syntax is:

ax.set_yscale("log")

Upvotes: 3

Cory Dolphin
Cory Dolphin

Reputation: 2670

http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.axis

Simply add the keyword argument log=True

Or, in an example:

from matplotlib import pyplot
import math
pyplot.plot([x for x in range(100)],[math.exp(y) for y in range(100)] )
pyplot.xlabel('arbitrary')
pyplot.ylabel('arbitrary')
pyplot.title('arbitrary')

#pyplot.xscale('log')
pyplot.yscale('log')

pyplot.show()

enter image description here

Upvotes: 18

Mike
Mike

Reputation: 20196

Instead of plot, you can use semilogy:

import numpy as npy
import matplotlib.pyplot as plt
x=npy.array([i/100. for i in range(100)])
y=npy.exp(20*x)
plt.semilogy(x, y)
plt.show()

But I'm not entirely sure what you hope to gain from using a log scale. When you say "small difference", do you mean that the values might be something like 193.000001 and 193.000002? If so, it might help to subtract off 193.

Upvotes: 2

Thanasis Petsas
Thanasis Petsas

Reputation: 4448

You can use this piece of code:

import matplotlib.pyplot
# to set x-axis to logscale
matplotlib.pyplot.xscale('log')
# to set y-axis to logscale
matplotlib.pyplot.yscale('log')

Upvotes: 2

Related Questions