在python中创建序列时寻找range()中的最后一个元素

0 人关注

我正在努力从可变长度的CSV中创建固定大小的序列。

我所使用的方式是一个函数

def create_sequences(csv, window_size, stride):
    sequences = []
    for i in range(0, len(csv)-window_size, stride):
        sequences.append(csv[i:i+window_size])
    return sequences
它成功地返回了序列，但数据丢失了，因为我已经创建了可视化并试图手动解决它，它缺少一些数据。
Total length = 115
Size = 30
Stride = 20
Ending size = 115 -30 = 85
First window: 0 -> 30 
Second Window: 20 -> 50
Third Window: 40 -> 70
Fourth Window: 60 -> 90
Fifth Window: 80 -> 110
The last five frames are lost, How can I set up a window from 100 -> 115 and pad the last row?


         
          python


         
          time-series


         
          lstm


         
          sequence


        
         
          
          
           Muhammad Anas Raza
          
         
         
          发布于
          
          2021-09-05


          
           已采纳


          
           
            你的
            
             range()
            
            没有包含足够的内容。你可以按以下方法修复for循环。
           
           def create_sequences(csv, window_size, stride):
    sequences = []
    for start in range(0, len(csv), stride):
        window = csv[start:start+window_size]
        if window == []:
            break
        sequences.append(window)
    return sequences
注意，在for循环中，我们需要测试窗口是否为空--这发生在序列的最后。在这种情况下，我们就知道我们已经完成了for循环，并脱离了。
Update
这里有一个更新，其中包括填充值，使所有的窗口都有相同的尺寸。
def create_sequences(csv, window_size, stride, padding=None):
    sequences = []
    for start in range(0, len(csv), stride):
        window = csv[start:start+window_size]
        if window == []:
            break
        if len(window) < window_size:
            window.extend((window_size - len(window)) * [padding])
        sequences.append(window)
    return sequences
使用实例。
for window in create_sequences(list(range(115)),30, 20, padding=-1):
    print(window)
Output:
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29]
[20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49]