Best way to generate an array of all possible integer numbers for a given base and number of digits

Question

Bill Tubbs 2021-6-8

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/851260-best-way-to-generate-an-array-of-all-possible-integer-numbers-for-a-given-base-and-number-of-digits

回答： Walter Roberson 2021-6-9

I want to prepare an array that contains all combinations in rows of possible sequences represented by an d-digit number of base b.

E.g. With n = 3 and b = 2 I came up with the following two ways to do it

d = 3; b = 2; n = b^n-1;
S = dec2base(0:n-1,b) == '1'

S =

7×3 logical array

0 0 0

0 0 1

0 1 0

0 1 1

1 0 0

1 0 1

1 1 0

This method works for d <=3 but not higher:

[B1,B2,B3] = meshgrid(0:b-1,0:b-1,0:b-1);
S = [B1(:) B2(:) B3(:)]

S =

0 0 0

0 1 0

1 0 0

1 1 0

0 0 1

0 1 1

1 0 1

1 1 1

The order of the sequences doesn't matter.

I'm sure there must be a simpler way!

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Answer 1

Walter Roberson 2021-6-9

1
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https://ww2.mathworks.cn/matlabcentral/answers/851260-best-way-to-generate-an-array-of-all-possible-integer-numbers-for-a-given-base-and-number-of-digits#answer_720240

在 MATLAB Online 中打开

d = 4; b = 3;
B = cell(1,d);
[B{:}] = ndgrid(0:b-1);
B = cellfun(@(M) M(:), B, 'uniform', 0);
S = [B{end:-1:1}];
S
S = 81×4
     0     0     0     0
     0     0     0     1
     0     0     0     2
     0     0     1     0
     0     0     1     1
     0     0     1     2
     0     0     2     0
     0     0     2     1
     0     0     2     2
     0     1     0     0