python的nan生成表示判决和忽略nan的统计运算

Posted 2022-11-28 飞凡可期

"""
nan 三种生成方法，判断方法，来源
"""
#Gen nan
xf = float('nan')

import numpy as np
xn = np.nan

from decimal import Decimal
xd = Decimal('nan')


# souce of nan, 'inf' -'inf', inf/inf
x1 = float('inf') + 2*float('inf')
x2 = float('inf') - float('inf')
x3 = float('inf') / float('inf')

# judge nan
print(xf != xf)
print(xn != xn)
print(xd != xd)

# nanmean, nanmax, nanmin, nanstd
ls = [2,3,4, xf]
print('mean = ', np.mean(ls))
print('nanmean = ', np.nanmean(ls))
print('nanmax = ', np.nanmax(ls))
print('nanmin = ', np.nanmin(ls))
print('nanstd = ', np.nanstd(ls))

ls.extend([str(xf), str(xd)])