Simple string and how to produce all possible combinations of numbers, letters and special characters

Hi everyone, I am facing some problem in using strings.

I want to produce all possible combinations of numbers,letters and special charactes.

for eg. a12,b12,c12,d12... 1a2,1a3,1a4,..1a9..1a, and so on and I want to pass these strings to some function in iterative for loop

If try to use for loop the problem will be as follows:

x='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz .,/<>?";:\|}]''{[=+-_)(*&^%$#@!~`';  
for i=1:length(x)  
    for j=1:length(x)  
   Data='x(i)x(j)'  
   Data1=sprintf('%X',Data);  
    .....  
    .....  
    end  
end

If i use for loop using 'x(i)x(j)' it will be considered as a single string. So for every loop it will produce same hex value!!

If I remove '' and only give x(i)x(j) it doesnt count as any data type and matlab will give error.

I want to use this Data1 hex value in another function , like this I want to increase the loop further to produce all possible strings with 3 places and 4 places and so on....

Please help me

Answer 1

[Guillaume]

This is basic string concatenation, achieved with [] (or horzcat, or strcat):

Data = [x(i), x(j)]

Or you could use sprintf:

Data = sprintf('%c%c', x(i), x(j))

However, using a loop for generating all combinations is a performance killer, particularly when you have a function, nchoosek, specially designed for that:

x='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz .,/<>?";:\|}]''{[=+-_)(*&^%$#@!~`';

allcombs = nchoosek(x, 2) 
allhexs = cellfun(@(c) sprintf('%X', c), num2cell(allcombs, 2), 'UniformOutput', false)

[sai charan bandi]

Thank You so much. nchoosek is awesome option but I have to use for loops anyway because I am trying to break one system using brute force(checking for all possible combinations), so it doesn't matter i think!