# Permutation ( IdxLst ; PermNr ; nObj )

Permutation of an index list

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Erich Schmidt - Show more from this author |

Permutation(""; 600000; 10)

Permutation(""; Factorial(5)-1; 6 )

1¶6¶9¶0¶4¶2¶3¶5¶7¶8

0¶5¶4¶3¶2¶1

Function definition: (Copy & paste into FileMaker's Edit Custom Function window)

The function returns one of the nObj! [ Factorial(nObj) ] possible permutations of the index list {0, 1, 2, …, nObj-1}

Parameters:

IdxLst must be empty

PermNr can be an integer between 0 and Factorial( nObj) - 1

nObj must be a positive integer

For different values of PermNr you get different permutations.

The PermNr=0 gives the index list in ascending order, PermNr=Factorial(nObj)-1 gives the index list in descending order.

Requires other CF: CustomList() [www.briandunning.com/cf/868]

Examples:

Permutation(""; 18 ; 4 ) returns "3¶0¶1¶2"

Permutation(""; 600000; 10) returns "1¶6¶9¶0¶4¶2¶3¶5¶7¶8"

CustomList ( 1 ; Factorial ( 4 ) ; "Substitute ( Permutation ( \"\" ; [n]-1 ; 4 ) ; \¶ ; \" \" ) ") returns "0 1 2 3 ¶0 1 3 2 ¶0 2 1 3 ¶ … ¶3 2 0 1¶3 2 1 0 " 24 lines

Notice:

To permute an arbitrary list $AnyList you can use the following statement sequence:

Let (

[

n = ValueCount($AnyList) ;

$PLIST = Permutation ( "" ; $PNR ; n )

];

CustomList ( 1 ; n ; "GetValue($AnyList; 1+GetValue($PLIST; [n]) )" )

)

where $PNR is the permutation number [an integer between 0 and factorial(n)-1 ].

For $AnyList ="alpa¶beta¶gamma¶delta¶epsilon¶zeta¶eta¶theta¶iota" and $PNR=270001 you get the following list:

eta

zeta

epsilon

alpa

beta

gamma

delta

iota

theta

## Comments

Note: these functions are not guaranteed or supported by BrianDunning.com. Please contact the individual developer with any questions or problems.