Filtered( list, func )
Filtered returns a new list that contains those elements of the list
list for which the unary function func returns
true. The order of
the elements in the result is the same as the order of the corresponding
elements of list. If an element, for which func returns
appears several times in list it will also appear the same number of
times in the result. list may contain holes, they are ignored by
Filtered. func must return either
false for every
element of list, otherwise an error is signalled.
gap> Filtered( [1..20], IsPrime ); [ 2, 3, 5, 7, 11, 13, 17, 19 ] gap> Filtered( [ 1, 3, 4, -4, 4, 7, 10, 6 ], IsPrimePowerInt ); [ 3, 4, 4, 7 ] gap> Filtered( [ 1, 3, 4, -4, 4, 7, 10, 6 ], > n -> IsPrimePowerInt(n) and n mod 2 <> 0 ); [ 3, 7 ]
The result is a new list, that is not identical to any other list. The elements of that list however are identical to the corresponding elements of the argument list (see Identical Lists).
Sublist (see Sublist) allows you to extract elements of a list
according to indices given in another list.
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