Generate specific binary combination

Hi guys,

I am working with binary combinations and encountering a problem with memory as the N value gets bigger. I am using this function to create my binary combinations array:

N = 4;
dec2bin(0:2^N-1) - '0'

I need to iterate each combination in the array in my calculation (i.e., iterating each row of the array at a time). Is there a way that we can generate a specific combination without having to create the whole array beforehand and use only one row at a time?

For example, 7th row in the array is [0 1 1 0]. I want to create [0 1 1 0], do the calculation, then continue to 8th row and so on.

Your inputs are much appreciated.

Answer 1

[Walter Roberson]

N = 4;
for K = 0 : 2^N - 1
    thiscombo = dec2bin(K,N);
    stuff
end

[Khoa Tran]

Thanks @Walter Roberson. This is just what I need.

Answer 2

[Chunru]

You can put the dec2bin inside the loop so it won't be a big array.

N = 4;
for i=0:2^N-1
    c = dec2bin(i, N) - '0'
end

c = 1×4

0 0 0 0

c = 1×4

0 0 0 1

c = 1×4

0 0 1 0

c = 1×4

0 0 1 1

c = 1×4

0 1 0 0

c = 1×4

0 1 0 1

c = 1×4

0 1 1 0

c = 1×4

0 1 1 1

c = 1×4

1 0 0 0

c = 1×4

1 0 0 1

c = 1×4

1 0 1 0

c = 1×4

1 0 1 1

c = 1×4

1 1 0 0

c = 1×4

1 1 0 1

c = 1×4

1 1 1 0

c = 1×4

1 1 1 1

[Khoa Tran]

Thanks @Chunru. A simple and effective solution.