问题
I have a problem with this plot:
[![enter image description here][1]][1]
The y-axis is in unit but I need them to be in millions as such:
[![enter image description here][2]][2]
Do you know a method to achieve this? Thanks in advance.
回答1:
You can use a custom FuncFormatter like this:
from matplotlib.ticker import FuncFormatter
import matplotlib.pyplot as plt
def millions(x, pos):
'The two args are the value and tick position'
return '%1.1fM' % (x * 1e-6)
formatter = FuncFormatter(millions)
fig, ax = plt.subplots()
ax.yaxis.set_major_formatter(formatter)
Or you can even replace millions with the following functions to support all magnitudes:
def human_format(num, pos):
magnitude = 0
while abs(num) >= 1000:
magnitude += 1
num /= 1000.0
# add more suffixes if you need them
return '%.2f%s' % (num, ['', 'K', 'M', 'G', 'T', 'P'][magnitude])
回答2:
import pandas as pd
import matplotlib .pyplot as plt
import matplotlib.ticker as ticker
fig, ax=plt.subplots()
ax.plot([1, 2], [1000000, 5000000])
scale_y = 1e6
ticks_y = ticker.FuncFormatter(lambda x, pos: '{0:g}'.format(x/scale_y))
ax.yaxis.set_major_formatter(ticks_y)
ax.set_ylabel('val in millions')
回答3:
You could use a FuncFormatter:
from matplotlib import pyplot as plt
from matplotlib.ticker import FuncFormatter
def millions_formatter(x, pos):
return f'{x / 1000000}'
fig, ax = plt.subplots()
ax.plot([1, 2], [1000000, 5000000])
ax.yaxis.set_major_formatter(FuncFormatter(millions_formatter))
ax.set_ylabel('value (in millions)')
plt.show()
来源：https://stackoverflow.com/questions/61330427/set-y-axis-in-millions