nchoosek (MATLAB Functions)

Binomial coefficient or all combinations

Syntax

```
C = nchoosek(n,k)
C = nchoosek(v,k)
```

Description

C = nchoosek(n,k) where n and k are nonnegative integers, returns . This is the number of combinations of things taken at a time.

C = nchoosek(v,k), where v is a row vector of length n, creates a matrix whose rows consist of all possible combinations of the elements of v taken at a time. Matrix C contains rows and columns.

Examples

The command nchoosek(2:2:10,4) returns the even numbers from two to ten, taken four at a time:

     2     4     6     8
     2     4     6    10
     2     4     8    10
     2     6     8    10
     4     6     8    10

Limitations

This function is only practical for situations where n is less than about 15.

See Also

perms

native2unicode ndgrid