Putting spaces between elements of a string/

I have found some graph resources that list the adjacency matrices as strings of numbers without spaces, such as:

011001110000

101111000000

110100011000

011010001100

010101000110

110010100010

100001010011

101000101001

001100010101

000110001011

000011100101

000000111110

I would like to insert spaces between each digit, so that I can use it as my adjacency matrix in Matlab. Is there a good way to do this? The matrices will all be square, but of different sizes.

[Stephen23]

https://xyproblem.info/

Answer 1

[John D'Errico]

A = ['011001110000';'101111000000';'110100011000';'011010001100';'010101000110';'110010100010';...
    '100001010011';'101000101001';'001100010101';'000110001011';'000011100101';'000000111110'];

Note that a simple sprintf statement can insert a space between elements in a string.

sprintf('%c ','011001110000')

ans = '0 1 1 0 0 1 1 1 0 0 0 0 '

So if we apply that format to A, we get...

B = sprintf('%c ',A)

B = '0 1 1 0 0 1 1 1 0 0 0 0 1 0 1 1 1 1 0 0 0 0 0 0 1 1 0 1 0 0 0 1 1 0 0 0 0 1 1 0 1 0 0 0 1 1 0 0 0 1 0 1 0 1 0 0 0 1 1 0 1 1 0 0 1 0 1 0 0 0 1 0 1 0 0 0 0 1 0 1 0 0 1 1 1 0 1 0 0 0 1 0 1 0 0 1 0 0 1 1 0 0 0 1 0 1 0 1 0 0 0 1 1 0 0 0 1 0 1 1 0 0 0 0 1 1 1 0 0 1 0 1 0 0 0 0 0 0 1 1 1 1 1 0 '

B = reshape(B,size(A,2)*2,[])'

B = 12×24 char array
    '0 1 1 0 0 1 1 1 0 0 0 0 '
    '1 0 1 1 1 1 0 0 0 0 0 0 '
    '1 1 0 1 0 0 0 1 1 0 0 0 '
    '0 1 1 0 1 0 0 0 1 1 0 0 '
    '0 1 0 1 0 1 0 0 0 1 1 0 '
    '1 1 0 0 1 0 1 0 0 0 1 0 '
    '1 0 0 0 0 1 0 1 0 0 1 1 '
    '1 0 1 0 0 0 1 0 1 0 0 1 '
    '0 0 1 1 0 0 0 1 0 1 0 1 '
    '0 0 0 1 1 0 0 0 1 0 1 1 '
    '0 0 0 0 1 1 1 0 0 1 0 1 '
    '0 0 0 0 0 0 1 1 1 1 1 0 '

There are probably many ways to have done this, but the above works. Another solution would be to do:

C = repmat(' ',[size(A)].*[1 2]);
C(:,1:2:end) = A

C = 12×24 char array
    '0 1 1 0 0 1 1 1 0 0 0 0 '
    '1 0 1 1 1 1 0 0 0 0 0 0 '
    '1 1 0 1 0 0 0 1 1 0 0 0 '
    '0 1 1 0 1 0 0 0 1 1 0 0 '
    '0 1 0 1 0 1 0 0 0 1 1 0 '
    '1 1 0 0 1 0 1 0 0 0 1 0 '
    '1 0 0 0 0 1 0 1 0 0 1 1 '
    '1 0 1 0 0 0 1 0 1 0 0 1 '
    '0 0 1 1 0 0 0 1 0 1 0 1 '
    '0 0 0 1 1 0 0 0 1 0 1 1 '
    '0 0 0 0 1 1 1 0 0 1 0 1 '
    '0 0 0 0 0 0 1 1 1 1 1 0 '

And again, it works. As I said, many ways...

Looking back at your question though, I think you want to turn the string array into an numeric array, to then be used as an adjacency matrix. And that is trivial. I never needed to go into the earlier artifices at all.

D = A - '0'

D = 12×12

0 1 1 0 0 1 1 1 0 0 0 0 1 0 1 1 1 1 0 0 0 0 0 0 1 1 0 1 0 0 0 1 1 0 0 0 0 1 1 0 1 0 0 0 1 1 0 0 0 1 0 1 0 1 0 0 0 1 1 0 1 1 0 0 1 0 1 0 0 0 1 0 1 0 0 0 0 1 0 1 0 0 1 1 1 0 1 0 0 0 1 0 1 0 0 1 0 0 1 1 0 0 0 1 0 1 0 1 0 0 0 1 1 0 0 0 1 0 1 1 0 0 0 0 1 1 1 0 0 1 0 1 0 0 0 0 0 0 1 1 1 1 1 0

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graph(D)

ans = 
  graph with properties:

    Edges: [30×2 table]
    Nodes: [12×0 table]

plot(graph(D))

[Walter Roberson]

D = A - '0'

is an excellent approach (though admittedly not an obvious one.)

[jeet-o]

Exactly what I needed. Thank you. And indeed I needed to use them as numerical elements to build adjacency matrices. I'm testing algorithms to assess graph isomorphisms. If anyone knows very difficult test pairs, please send them.

[jeet-o]

Once again, what a neat solution - now of course I'm wondering WHY that works?

[Stephen23]

"now of course I'm wondering WHY that works?"

It simply subtracts the character code of '0' from the other character codes. Unicode character codes are briefly introduced here:

https://www.mathworks.com/help/matlab/matlab_prog/unicode-and-ascii-values.html

Like everything else on your computer, text just consists of numbers, so there is no reason why they cannot be subtracted, multiplied, added, etc.

[jeet-o]

Thank you, That's very instructive - I've spent little time on character strings (like zero!) - I'll bone up on the topic.

[Walter Roberson]

@jeet-o

Note that something like '1001' is known to MATLAB as being a character vector, whereas "1001" is known to MATLAB as being a character string . The characters in character vectors are individually addressible

A = '0100'

A = '0100'

A(2)

ans = '1'

and you can do arithmetic on them.

A(2) + 2

ans = 51

char(ans)

ans = '3'

whereas fpr character strings indexing refers to an entire group

B = ["0100", "1001"]

B = 1×2 string array
    "0100"    "1001"

B(2)

ans = "1001"

and the + operator means something different:

B(2) + 2

ans = "10012"

Answer 2

[Matt J]

A=['011001110000'
   '101111000000'
   '110100011000'
   '011010001100'
   '010101000110'
   '110010100010'
   '100001010011'
   '101000101001'
   '001100010101'
   '000110001011'
   '000011100101'
   '000000111110'];

B=join(string(A-'0'), ' ',2)

B = 12×1 string array
    "0 1 1 0 0 1 1 1 0 0 0 0"
    "1 0 1 1 1 1 0 0 0 0 0 0"
    "1 1 0 1 0 0 0 1 1 0 0 0"
    "0 1 1 0 1 0 0 0 1 1 0 0"
    "0 1 0 1 0 1 0 0 0 1 1 0"
    "1 1 0 0 1 0 1 0 0 0 1 0"
    "1 0 0 0 0 1 0 1 0 0 1 1"
    "1 0 1 0 0 0 1 0 1 0 0 1"
    "0 0 1 1 0 0 0 1 0 1 0 1"
    "0 0 0 1 1 0 0 0 1 0 1 1"
    "0 0 0 0 1 1 1 0 0 1 0 1"
    "0 0 0 0 0 0 1 1 1 1 1 0"

Answer 3

[Catalytic]

A=['011001110000'
   '101111000000'
   '110100011000'
   '011010001100'
   '010101000110'
   '110010100010'
   '100001010011'
   '101000101001'
   '001100010101'
   '000110001011'
   '000011100101'
   '000000111110'];

G=graph(A>'0');

plot(G)

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