[英]Python append 2D numpy array to 3D
我遇到了 numpy arrays 的理解問題。我有一個數據集,閱讀時看起來像這樣:
[
[ F0, F1, F2, F3 ... F22],
[ G0, G1, G2, G3 ... G22],
[ H0, H1, H2, H3 ... H22],
[ I0, I1, I2, I3 ... I22],
[ J0, J1, J2, J3 ... J22]
]
我想將它們轉換為“三個一組”:
[
[
[ F0, F1, F2, F3 ... F22],
[ G0, G1, G2, G3 ... G22],
[ H0, H1, H2, H3 ... H22]
],
[
[ G0, G1, G2, G3 ... G22],
[ H0, H1, H2, H3 ... H22],
[ I0, I1, I2, I3 ... I22]
]
...
]
到目前為止,我已經寫了這段代碼:
data = loadtxt('./training_data/set_0.csv', delimiter=';')
batch_size=3
features=17
labels=6
trainX = np.empty((0,batch_size, features), float)
for i in range(0, len(data)-batch_size):
row_X = data[i:i+batch_size,0:features]
trainX = np.append(trainX, row_X)
print(trainX[0])
記錄 row_X 的形狀可以得到我想要的(3,17)
。 但是trainX
變量似乎包含那些 arrays 的平面組合,我本trainX[0]
的形狀是(batch_size,features)
。
import numpy as np
batch_size = 3
l = np.array([
[1,2,3,4,5],
[ 2,3,4,5,6],
[ 3,4,5,6,7],
[ 4,5,6,7,8],
[ 5,6,7,8,9],
[6,7,8,9,0],
])
output = [l[n:n+batch_size] for n in range(len(l)-batch_size+1)]
Output
[array([[1, 2, 3, 4, 5],
[2, 3, 4, 5, 6],
[3, 4, 5, 6, 7]]),
array([[2, 3, 4, 5, 6],
[3, 4, 5, 6, 7],
[4, 5, 6, 7, 8]]),
array([[3, 4, 5, 6, 7],
[4, 5, 6, 7, 8],
[5, 6, 7, 8, 9]]),
array([[4, 5, 6, 7, 8],
[5, 6, 7, 8, 9],
[6, 7, 8, 9, 0]])]
假設您有一個二維 numpy 數組,如下所示:
arr = array([[7, 9, 4, 1, 0],
[9, 5, 1, 8, 5],
[6, 1, 9, 7, 1],
[2, 8, 4, 8, 7],
[1, 2, 6, 1, 8],
[0, 2, 7, 0, 2]])
為了將其轉換為三維數組,您可以使用reshape
function:
arr.reshape(3, 2, -1)
這給你三個“批次”,每批兩行。
array([[[7, 9, 4, 1, 0],
[9, 5, 1, 8, 5]],
[[6, 1, 9, 7, 1],
[2, 8, 4, 8, 7]],
[[1, 2, 6, 1, 8],
[0, 2, 7, 0, 2]]])
最后一個參數-1
告訴reshape
,在給定數組中元素的實際數量和其他維度的大小的情況下,計算第三維的大小。
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