在MATLAB中根据另一个矩阵值复制矩阵值

Question

Hi I am trying to perform this on MATLAB

A =

64     2     3    61    60     6     7    57
 9    55    54    12    13    51    50    16
17    47    46    20    21    43    42    24
40    26    27    37    36    30    31    33
32    34    35    29    28    38    39    25
41    23    22    44    45    19    18    48
49    15    14    52    53    11    10    56
 8    58    59     5     4    62    63     1

I want to select values from A based on F

F =

 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    -1    -1    -1    -1
 0     0     0     0     0     0     0     0
-1    -1    -1    -1    -1    -1    -1    -1
-1    -1    -1    -1    -1    -1    -1    -1
-1    -1    -1    -1    -1    -1    -1    -1

I want this output

u =

40    26    27    37    36    30    31    33
41    23    22    44    45    19    18    48
49    15    14    52    53    11    10    56
 8    58    59     5     4    62    63     1

This means that I want all the values corresponding to '-1' in a matrix. i tried u=A(F==-1) ... but it gives me a single column with all the values like this:

u =

40
41
49
 8
26
23
15
58
27
22
14
59
37
44
52
 5
36
45
53
 4
30
19
11
62
31
18
10
63
33
48
56
 1

Answer 1

This will do it:-

u=-A.*F;               
u(all(u==0,2),:)=[]    %Removing rows containing zeros

Another solution:-

u=reshape(A(F==-1),4,8)