python - 在python中查找矩阵行的变化

Question

我有一个用 0 和 1 编码的 NxM 矩阵 - 其中只有 1 要打印在其各自的位置，而 0 是空格，例如以下矩阵:

 m = [[0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0]
      [0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0]
      [0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0]
      [0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0]
      [0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0]
      [0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0]
      [1 1 1 1 0 0 0 0 1 1 1 1 1 1 0 0 0 0 1 1]

我的问题是如何从每一行中从 0 到 1 发生的变化创建起点，并从从 1 到 0 发生的变化创建终点。然后打印起点和终点之间所有的1

我有以下代码(不起作用):

nrows, ncols = m.shape #gets the shape of the matrix
for r in range(nrows):
  for c in range(ncols):
    if m[r,c] == 0 and m[r,c+1] == 1: #checks if there is a 0 first and then a 1 in the next index of the column in the row to create a starting point
       start = m[r,c+1]
    if m[r,c] == 1 and m[r,c+1] == 0: #checks if there is a 1 first and then a 0 in the next index of the column in the row to create an end point
       end = m[r, c+1]

我想要的输出是，例如考虑最后一行:

It should print everything between the first 1 and last 1 before a 0 is found in that row, excluding the 0s. So basically this: 1 1 1 1....1 1 1 1 1 1....1 1 The dots (.)represent the 0s that have to be excluded All help and advice will be highly appreciated.

Answer 1

您的目标是打印输出还是指示 1 开始和结束位置的标记？如果您的目标只是打印输出，为什么不做一些简单的事情，例如:

m = [[0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0],
     [0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0],
     [0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
     [0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
     [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0],
     [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0],
     [1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1]
]

for row in m:
    for bit in row:
        print(bit or ' ', end=' ')
    print()

输出

              1 1 1 1                   
              1 1 1 1                   
          1 1 1 1                       
          1 1 1 1                       
                            1 1 1 1     
                            1 1 1 1     
1 1 1 1         1 1 1 1 1 1         1 1 

按照您认为合适的方式进行操作，以消除零的空格或 1 之间的空格(即 ' ' 空格与 '' 空字符串。)

Do you mind showing/explaining on how I am able to get the markers where the 1s begin and end?

借用 Identify groups of continuous numbers in a list 的 SO 答案，我们可以这样做:

for row in m:
    indicies = compress(count(), row)

    ranges = []

    for _, g in groupby(enumerate(indicies), lambda x: x[0] - x[1]):
        group = [x[1] for x in g]
        ranges.append((group[0], group[-1]))

    print(ranges)

输出

[(7, 10)]
[(7, 10)]
[(5, 8)]
[(5, 8)]
[(14, 17)]
[(14, 17)]
[(0, 3), (8, 13), (18, 19)]