Question

我有下面的代码，实际上是检查数据中是否有任何小于0.5的值，将替换为-1，但我想检查一个特定的位置值是否应该只检查第10个值！我怎么能这样做，使用numpy的功能

prf

这就是想要的。

import numpy as np
x = np.random.random((10,10))
x2 = np.where( x<0.5, x, -1)
print(x2)

Answer 1

一种方法是在切片后检查第10列的掩码，即

import numpy as np
x = np.random.random((10,10))

选项1 ：

mask = x[:, 9] <0.5
x[:, 9][mask] = -1

选项2

x[:,9] = np.where(x[:, 9] <0.5,x[:,9],-1)

输出：

array([[ 0.13291679,  0.36437627,  0.61680761,  0.47180988,  0.40779945,
     0.21448173,  0.70938531,  0.88205403,  0.9007378 , -1.        ],
   [ 0.18517135,  0.591143  ,  0.20951978,  0.09811755,  0.53492105,
     0.70484089,  0.87912825,  0.94987278,  0.98151354, -1.        ],
   [ 0.55545461,  0.50936625,  0.26460411,  0.81739966,  0.07142206,
     0.97005035,  0.08655628,  0.62414457,  0.42844278,  0.67848139],
   [ 0.97279637,  0.32032396,  0.87051124,  0.01823881,  0.58417096,
     0.39085964,  0.39753232,  0.49915164,  0.44284544, -1.        ],
   [ 0.95868029,  0.39688236,  0.82069431,  0.30433585,  0.52959998,
     0.88929817,  0.90156477,  0.09418035,  0.68805644,  0.97685649],
   [ 0.11680575,  0.97914842,  0.34087048,  0.16332758,  0.0531713 ,
     0.18936729,  0.02451479,  0.25073047,  0.72354052, -1.        ],
   [ 0.65997478,  0.60118864,  0.42100758,  0.16616609,  0.16181439,
     0.83024903,  0.99521926,  0.45748708,  0.26720405,  0.92070836],
   [ 0.99248054,  0.68889428,  0.30094476,  0.00427059,  0.27930388,
     0.44895715,  0.3866733 ,  0.40558292,  0.4394462 , -1.        ],
   [ 0.98661531,  0.57641035,  0.17323863,  0.17630214,  0.27312168,
     0.14315776,  0.10212816,  0.15961012,  0.55773218, -1.        ],
   [ 0.68539788,  0.58486093,  0.12482709,  0.89666695,  0.83484223,
     0.39818926,  0.66773542,  0.59832267,  0.28018467, -1.        ]])

numpy.where数据位置以及条件

1 个答案: