Select

Select({e1, e2, ...}, head)

returns a list of the elements ei for which head(ei) returns True.

Examples

Find numbers greater than zero:

>> Select({-3, 0, 1, 3, a}, #>0&)
{1,3}

Select works on an expression with any head:

>> Select(f(a, 2, 3), NumberQ)
f(2,3)

Nonatomic expression expected.

>> Select(a, True)
Select(a,True)

Select all Listable system function names.

>> Select(Names("System`*"), MemberQ(Attributes(#), Listable) &)

Related terms

Cases, Pick

Implementation status

• ✅ - full supported

Github

• Implementation of Select