# how to get the all possible combination between two range of numbers

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Sun Heat on 29 Jun 2018
Commented: Steven Lord on 29 Jun 2018
every time this code iterate random number between 1 to 4. for 1st iteration c=2 and g=2. for second iteration c=1 and g=2; i need never the combination repeated once it comes
xx=4
c= randi(length(xx))
g= randi(length(xx))
Stephen23 on 29 Jun 2018
Edited: Stephen23 on 29 Jun 2018
xx=4
c= randi(length(xx))
g= randi(length(xx))
xx is scalar, so length(xx) is 1, which means both randi calls will always produce the same output:
>> xx = 4;
>> randi(length(xx))
ans = 1
>> randi(length(xx))
ans = 1
>> randi(length(xx))
ans = 1
>> randi(length(xx))
ans = 1
>> randi(length(xx))
ans = 1
>> randi(length(xx))
ans = 1
>> randi(length(xx))
ans = 1
... etc
Is this the intended behavior?
Sun Heat on 29 Jun 2018
xx=1:4

KL on 29 Jun 2018
The example and description is a but confusing but if you ask how to get the all possible combination between two range of numbers, use perms
my_range = 1:4; %or even [1 3 5]...
c = perms(my_range)
Sun Heat on 29 Jun 2018
thanks.....this works....but i need to know is there any function in matlab to do so as our number of variable(c,g,etc) increases....
Steven Lord on 29 Jun 2018
How many variables are you planning to use and how many values will each variable be able to take on? If you want to solve with too many variables or with variables that can take on too many different values, you may need to consider a new approach for solving your problem that avoids combinatorial explosion.