Wolfram Function Repository
Instant-use add-on functions for the Wolfram Language
Function Repository Resource:
Get permutations that satisfy a certain criterion
ResourceFunction["SelectPermutations"][list,crit] generates a list of all possible permutations of the elements in list satisfying crit. | |
ResourceFunction["SelectPermutations"][list,n,crit] gives all permutations containing at most n elements satisfying crit. | |
ResourceFunction["SelectPermutations"][list,{n},crit] gives all permutations containing exactly n elements satisfying crit. | |
ResourceFunction["SelectPermutations"][…,crit,m] gives at most m results. |
Select from the list {5,6,7,8,9} those permutations that form a prime when concatenating the digits:
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Select those permutations having length 3:
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Select those permutations having length 3–4:
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Select permutations of {1,2,3,4} for which the first two elements and the last elements add up to the same value:
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Select the first 10 permutations of length 4 for which the elements add up to an odd number:
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Select polynomials for which the slope is 1 at x=0:
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Confirm that the slope is indeed unity at x=0:
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Duplicated items are treated the same:
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The main difference between SelectPermutations[list,crit] and Select[Permutations[list],crit] is the memory usage:
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Using Select and Permutations uses 500 times more memory:
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Verify that the results are identical:
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Head does not have to be List:
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SelectPermutations might take longer as it is written in higher-level code as compared to the implementation of Permutations:
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Using the built-in functions is faster at the expense of 500× more memory:
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