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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) &)

Cases, Pick

Implementation status

  • ✅ - full supported

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