removeIfNot()

Synopsis

Return a copy of the input list , having removed all members for which the function fun returns False .

Syntax

removeIfNot ( fun As Name, _
              list As List ) As Any 

Argument	Type	Description
fun	Name	The name of the function to apply; the function must return a boolean .
list	List	The list of arguments to which the test function will be applied.

Example 1

Intent >removeIfNot(:empty?, {{}, {:b}, {}, {:d}}) 
--> {{}, {}} 

Returns only empty lists in a list of lists . That is, the non-empty sublists have been removed.

Example 2

Using a custom function

Intent >removeIfNot(string?, {:a, :c, "b", :d, 3, {3}, "3", 2, 1}) 
--> {"b", "3"} 

In this example, only non-integers were returned using the following custom function:

Function string?(item As Any) As Boolean 
    string? = (typeName(item) = :string)
End Function 

Example 3

Intent >removeIfNot(:even?, {1, 2, 3, 4, 5, 6, 7, 8}) 
--> {2, 4, 6, 8} 

Here, the odd (not even) items have been removed from the result.