c = cell (2,2)
     ⇒ c =

         {
           [1,1] = [](0x0)
           [2,1] = [](0x0)
           [1,2] = [](0x0)
           [2,2] = [](0x0)
         }

c1 = cell (3, 4, 5);
c2 = cell ( [3, 4, 5] );
size (c1)
     ⇒ ans =
         3   4   5

作为创建空元胞数组然后填充它们的替代方案,可以使用num2cell, mat2cell和cellslices函数。

: C = num2cell (A) ¶

: C = num2cell (A, dim) ¶

转换数字矩阵A到元胞数组。

当否dim的每个元素A成为输出中的1x1元素C.

如果dim则定义的各个元素C包含中的所有元素A沿着指定的尺寸。dim也可以是应用相同规则的维度的avector。

例如

x = [1,2;3,4]
⇒
    1    2
    3    4

## each element of A becomes a 1x1 element of C
num2cell (x)
   ⇒
      {
        [1,1] =  1
        [2,1] =  3
        [1,2] =  2
        [2,2] =  4
      }
## all rows (dim 1) of A appear in each element of C
num2cell (x, 1)
   ⇒
      {
        [1,1] =
           1
           3
        [1,2] =
           2
           4
      }
## all columns (dim 2) of A appear in each element of C
num2cell (x, 2)
   ⇒
      {
        [1,1] =
           1   2
        [2,1] =
           3   4
      }
## all rows and cols appear in each element of C
## (hence, only 1 output)
num2cell (x, [1, 2])
   ⇒
      {
        [1,1] =
           1   2
           3   4
      }

详见: mat2cell.

广告

: C = mat2cell (A, dim1, dim2, …, dimi, …, dimn) ¶

: C = mat2cell (A, rowdim) ¶

转换矩阵A到元胞数组C.

每个维度参数(dim1, dim2等)是一个元素向量,它指定如何在输出中的新元素中划分该维度的元素C。中的元素数量i-维度是size (A, i)。因为中的所有元素A必须分区,有一个要求sum (dimi) == size (A, i)。输出数组的大小C是numel(dim1)xnumel(dim2)x…x数字(dimn).

给定一维参数,rowdim,输出按指定划分为行。所有其他维度都没有划分,因此所有列(dim 2)、页(dim 3)等都出现在每个输出元素中。

示例

x = reshape (1:12, [3, 4])'
⇒
    1    2    3
    4    5    6
    7    8    9
   10   11   12

## The 4 rows (dim1) are divided in to two cell elements
## with 2 rows each.
## The 3 cols (dim2) are divided in to three cell elements
## with 1 col each.
mat2cell (x, [2,2], [1,1,1])
⇒
{
  [1,1] =

     1
     4

  [2,1] =

      7
     10

  [1,2] =

     2
     5

  [2,2] =
      8
     11

  [1,3] =

     3
     6

  [2,3] =
      9
     12
}

## The 4 rows (dim1) are divided in to two cell elements
## with a 3/1 split.
## All columns appear in each output element.
mat2cell (x, [3,1])
⇒
{
  [1,1] =

     1   2   3
     4   5   6
     7   8   9

  [2,1] =

     10   11   12
}

详见: num2cell, cell2mat.

广告

: sl = cellslices (x, lb, ub, dim) ¶

给定一个数组x,此函数从索引向量确定的数组中生成切片的元胞数组lb, ub,分别用于下限和上限。

换句话说,它等效于以下代码:

n = length (lb);
sl = cell (1, n);
for i = 1:length (lb)
  sl{i} = x(:,...,lb(i):ub(i),...,:);
endfor

索引的位置从dim如果未指定,则沿第一个非奇异维度进行切片。

详见: cell2mat, cellindexmat, cellfun.

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