matplotlib: format axis offset-values to whole numbers or specific number

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I have a matplotlib figure which I am plotting data that is always referred to as nanoseconds (1e-9). On the y-axis, if I have data that is tens of nanoseconds, ie. 44e-9, the value on the axis shows as 4.4 with a +1e-8 as an offset. Is there anyway to force the axis to show 44 with a +1e-9 offset?

The same goes for my x-axis where the axis is showing +5.54478e4, where I would rather it show an offset of +55447 (whole number, no decimal - the value here is in days).

I've tried a couple things like this:

p = axes.plot(x,y)
p.ticklabel_format(style='plain')

for the x-axis, but this doesn't work, though I'm probably using it incorrectly or misinterpreting something from the docs, can someone point me in the correct direction?

Thanks, Jonathan

Problem illustration

I tried doing something with formatters but haven't found any solution yet...:

myyfmt = ScalarFormatter(useOffset=True)
myyfmt._set_offset(1e9)
axes.get_yaxis().set_major_formatter(myyfmt)

and

myxfmt = ScalarFormatter(useOffset=True)
myxfmt.set_portlimits((-9,5))
axes.get_xaxis().set_major_formatter(myxfmt)

On a side note, I'm actually confused as to where the 'offset number' object actually resides...is it part of the major/minor ticks?

matplotlib python
8 Answers

Similar to Amro's answer, you can use FuncFormatter

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.ticker import FuncFormatter

# Generate some random data...
x = np.linspace(55478, 55486, 100) 
y = np.random.random(100) - 0.5
y = np.cumsum(y)
y -= y.min()
y *= 1e-8

# Plot the data...
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(x, y, 'b-')

# Force the y-axis ticks to use 1e-9 as a base exponent 
ax.yaxis.set_major_formatter(FuncFormatter(lambda x, pos: ('%.1f')%(x*1e9)))
ax.set_ylabel('microseconds (1E-9)')

# Make the x-axis ticks formatted to 0 decimal places
ax.xaxis.set_major_formatter(FuncFormatter(lambda x, pos: '%.0f'%x))
plt.show()
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