1D series to 2D stacked

Hi,

I`m trying to think in a best option to "convert" a 1d arrays to a 2d as follows:

B has a fixed size of 10000x(a prior know number, here 6), so it just need to stack number 1's regarding the number into the aray A.

A =

1 5 3 1 2 4

B =

....

....

....

0 1 0 0 0 0

0 1 0 0 0 1

0 1 1 0 0 1

0 1 1 0 1 1

1 1 1 1 1 1 % ROW 1

It can be done maniulating the arrays in a slow way, I would like to do much faster.

Thanks

[Kevin Chng]

Hi,

to stack number 1's regarding the number into the aray A?Do you mind to elaborate the relationship between A and B?

[Walter Roberson]

Kevin, read the output B from the bottom upwards. The first column has one 1, which is the same number as A(1). The second column has five 1, which is the same number as A(2). And so on. So if you were to sum(B) then you would get A, with it always being the last so-many entries that are set to 1.

Answer 1

[Stephen23]

In one line:

B = A>=(10000:-1:1).'

Or for versions prior to R2016b:

B = bsxfun(@ge,A,(10000:-1:1).');

[Walter Roberson]

Note: This requires R2016b or later

[Eduardo Santos]

Thanks!

Answer 2

[Walter Roberson]

t = fliplr(1 : 10000);
B = t.' <= A;

This requires R2016b or later. For earlier releases, change the B line to

B = bsxfun(@le, t.', A);

[Eduardo Santos]

Thanks!