OpenMusic Reference
permutations
permutations
(combinatorial module) -- returns a exhaustive list of all the permutations of a list
Syntax
permutations bag
Inputs
| name | data type(s) | comments |
|---|---|---|
| bag | a list or tree | the ‘bag’ of elements to draw from |
Output
| output | data type(s) | comments |
|---|---|---|
| first | a tree | since the input is a list, the output is necessarily a list of lists, a tree |
Description
Returns a list containing all the possible permutations of the master list, bag . For example, if the list is (1 2) then there are two possible permutations of those elements: (1 2) and (2 1). If the list is (1 2 3) then there are six possibilities: (1 2 3), (1 3 2), (2 1 3), (2 3 1), (3 1 2), and (3 2 1). permutations respects nesting, i.e. only first-level elements of the tree are permuted- sublists are not touched.
Note also that for permutations , the list (1 1 1) still has 6 permutations, all of which are (1 1 1).
 |
permutations is a recursive function. Processing large lists with it may therefore result in an out of memory error.
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