numpy中布尔型数组的处理方法

来源：互联网发布：c语言提高书籍编辑：程序博客网时间：2024/06/06 10:02

布尔数组的操作方式主要有两种，any用于查看数组中是否有True的值，而all则用于查看数组是否全都是True。

如果用于计算的时候，布尔量会被转换成1和0，True转换成1，False转换成0。通过这种方法可以统计一个布尔量数组中True的个数。

如果普通的数组用于布尔类操作，也会有类似的数据类型转换。其中，非0的数值转换成True，而0则被转换成False。

In [30]: arr = randn(100)

In [31]: arr

Out[31]:

array([ 1.38474589, -1.51489066,-0.81053544, 1.47875437, -0.53638642,

0.09856211, 1.39931492,-0.04226221, -0.66064836, 0.31829036,

-0.33759781, -0.35793518, 0.66974626, 1.5989403 , 0.98361013,

0.0209635 , -0.56165749, 0.59473585, -0.06956145, -0.50384339,

-0.51207066, -0.41794862, 2.12230002, 0.55457739,-0.83156748,

-1.5609328 , -0.72414846, -0.24781724, 2.1523153 , -1.35802819,

1.75644258, 1.66794885,-0.30311682, 0.29060339, -0.18960502,

-0.91537419, -0.10277047, 0.06899507, 0.1535801 , 0.5281243 ,

-0.49951785, 0.26074368,-0.04215356, -0.29765383, -0.77197024,

0.72333408, -0.9656567 , -0.04391422, -0.53504402, -0.3695063 ,

-0.57323435, -0.09923021, -0.8819845 , -0.31904228, -0.34805511,

-1.39372713, -0.32243494, 1.18074562, -0.77189808, 0.14011272,

-0.12029721, 0.91164114, 0.3052017 , -0.45764259, 0.73858783,

0.67327449, 0.84294828, 0.54471476, 0.8300902 , -0.21001427,

-0.8247486 , 0.29870036,-0.71204709, 0.46825521, -0.76507537,

-0.67755756, 1.38798882, 0.44536155, 0.41104869, -0.24990925,

-0.38003931, 1.13801121, 0.19761371, 0.84638972, 1.05816446,

-0.03591458, 2.35862529, 1.69183501, 0.77490116, -1.47556029,

-0.54755786, -0.93202001, 0.69240349, -0.02720469, 0.49363318,

0.55501151, -1.67184849, -1.61725652, -0.95964244, 0.12177363])

In [32]: arr > 0

Out[32]:

array([ True, False, False, True, False, True, True, False, False,

True, False, False, True, True, True, True, False, True,

False, False, False, False, True, True, False, False, False,

False, True, False, True, True, False, True, False, False,

False, True, True, True, False, True, False, False,False,

True, False, False, False, False, False, False, False, False,

False, False, False, True,False, True, False, True, True,

False, True, True, True, True, True, False, False, True,

False, True, False, False, True, True, True, False, False,

True, True, True, True, False, True, True, True, False,

False, False, True, False, True, True, False, False, False, True],dtype=bool)

In [33]: (arr > 0).sum()

Out[33]: 46

In [34]: arr.any()

Out[34]: True

In [35]: arr.all()

Out[35]: True

In [36]: (arr > 0).all()

Out[36]: False

0 0