MATLAB: Nchoosek help

#nchoosekcombinationsvector

I am trying to figure out the nchoosek command but can't seem to get it. What I am trying to answer is if there are 4 people in a line, how many different ways can they be arranged. I tried nchoosek(1:4,4) but that returns the vector 1 2 3 4 and nchoosek(4,4) but that returns just a 1. What am I missing here?

Best Answer

Hi Sean, 4 people in a line is just factorial(4). nchoosek assumes you are interested in how many ways you can choose a number of objects out of set where order is not important. Note that arrangement in a circle is different.

Wayne

Related Solutions

MATLAB: I have 6 numbers with repetation : 1,2,2,3,3,4. I want all possible combinations using any 4 of the numbers. How will I get that

You can still use nchoosek. Just use it to create indices into the vector rather than the vector itself:

v = [1,2,2,3,3,4];
Idx = nchoosek(1:size(v,2),4);
Out = v(Idx)
Out =
     1     2     2     3
     1     2     2     3
     1     2     2     4
     1     2     3     3
     1     2     3     4
     1     2     3     4
     1     2     3     3
     1     2     3     4
     1     2     3     4
     1     3     3     4
     2     2     3     3
     2     2     3     4
     2     2     3     4
     2     3     3     4
     2     3     3     4

Note the difference between ‘Idx’ and ‘’Out.

MATLAB: Different combination of numbers

perms([1 2 3])

Refer perms

Best Answer

Related Solutions

MATLAB: I have 6 numbers with repetation : 1,2,2,3,3,4. I want all possible combinations using any 4 of the numbers. How will I get that

MATLAB: Different combination of numbers

Related Question