vstack方法
import numpy as np
a1 = np.random.randint(1,100,size = (3,4))
a2 = np.random.randint(1,100,size = (1,4))
a1
array([[26, 8, 77, 22],
[40, 84, 89, 88],
[46, 14, 66, 40]])
a2
array([[ 4, 88, 85, 55]])
- 将俩个行不相同列相同的数组进行拼接
- 把 a2往 a1上加 np.vstack([a1,a2])
从下往上加
a3 = np.vstack([a1,a2])
a3
array([[26, 8, 77, 22],
[40, 84, 89, 88],
[46, 14, 66, 40],
[ 4, 88, 85, 55]])
2. 列的拼接
hstack方法
import numpy as np
a1 = np.random.randint(1,100,size = (3,4))
a2 = np.random.randint(1,100,size = (3,7))
a1
array([[47, 59, 68, 22],
[76, 42, 8, 97],
[69, 26, 33, 91]])
a2
array([[74, 35, 6, 79, 71, 62, 90, 70],
[48, 82, 9, 76, 48, 42, 98, 85],
[ 8, 2, 27, 12, 21, 36, 65, 78]])
- 将俩个行相同列不相同的数组进行拼接
- 就是 a2从右边往 a1的左边加
从右往左加
a3 = np.hstack([a1,a2])
a3
array([[47, 59, 68, 22, 74, 35, 6, 79, 71, 62, 90, 70],
[76, 42, 8, 97, 48, 82, 9, 76, 48, 42, 98, 85],
[69, 26, 33, 91, 8, 2, 27, 12, 21, 36, 65, 78]])
3.行列都可以拼接的方法（axis=1拼接列，axis=0拼接行）
concatenate方法
a1
array([[68, 96, 15, 77],
[89, 61, 45, 83],
[89, 11, 74, 9]])
a2
array([[ 5, 43, 96, 65, 25, 51, 76, 24],
[54, 36, 52, 22, 70, 83, 77, 69],
[55, 53, 48, 78, 48, 75, 64, 80]])
np.concatenate((a1,a2),axis = 1)
array([[68, 96, 15, 77, 5, 43, 96, 65, 25, 51, 76, 24],
[89, 61, 45, 83, 54, 36, 52, 22, 70, 83, 77, 69],
[89, 11, 74, 9, 55, 53, 48, 78, 48, 75, 64, 80]])
4.转置（行列互换）
a1.T
a1
array([[68, 96, 15, 77],
[89, 61, 45, 83],
[89, 11, 74, 9]])
a1.T
array([[68, 89, 89],
[96, 61, 11],
[15, 45, 74],
[77, 83, 9]])
2.数组的分割
a = np.arange(16).reshape((4,4))
a
array([[ 0, 1, 2, 3],
[ 4, 5, 6, 7],
[ 8, 9, 10, 11],
[12, 13, 14, 15]])
1.上下分割成俩部分（也可以分割成四部分，一部分）
vsplit array_spli
np.array_split(a,2,axis=0) axis = 0以x轴进行分割
np.vsplit(a,2)
[array([[0, 1, 2, 3],
[4, 5, 6, 7]]),
array([[ 8, 9, 10, 11],
[12, 13, 14, 15]])]
2.左右分割成俩部分
hsplit array_split
np.array_split(a,2,axis=1) 以y轴分割axis=1
np.hsplit(a,2)
[array([[ 0, 1],
[ 4, 5],
[ 8, 9],
[12, 13]]),
array([[ 2, 3],
[ 6, 7],
[10, 11],
[14, 15]])]
