今天看到某个代码中有这个形式,查阅资料才懂了什么意思
import numpy as np
array = np.array([
[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12],
[13, 14, 15, 16]
])#数组一定要通过np形成,不然会报错
a = array[:, :]
print(a)
#[[ 1 2 3 4]
[ 5 6 7 8]
[ 9 10 11 12]
[13 14 15 16]]
b = array[:1, :]
print(b)
#[[1 2 3 4]]
c = array[:, :1]
print(c)
#[[ 1]
[ 5]
[ 9]
[13]]
d = array[:2, :]
print(d)
#[[1 2 3 4]
[5 6 7 8]]
e = array[1:2, :]
print(e)
#[[5 6 7 8]]
懂了吧,就是这样来选择行列
不过如果想把某行变成一个一维数组可以这样(其实我也不太懂)
array = np.array([
[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12],
[13, 14, 15, 16]
])
a = array[0, :]
print(a)
#[1 2 3 4]
b = array[:, 0]
print(b)
#[ 1 5 9 13]
c = array[:, 1]
print(c)
#[ 2 6 10 14]
d = array[1:3, 1]
print(d)
#[ 6 10]