PositionProperty( list, func )
PositionProperty
returns the position of the first element in the list
list for which the unary function func returns true
. list must
not contain holes. If func returns false
for all elements of list
false
is returned. func must return true
or false
for every
element of list, otherwise an error is signalled.
gap> PositionProperty( [10^7..10^8], IsPrime ); 20 gap> PositionProperty( [10^5..10^6], > n -> not IsPrime(n) and IsPrimePowerInt(n) ); 490
First
(see First) allows you to extract the first element of a list
that satisfies a certain property.
GAP 3.4.4