Invert boolean value of its argument.

Related Syntax Constructs

The following construct(s) refer to this construct:

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Syntax

fn:not(sequence $sequence) => boolean

Description

This function returns true, if the effective boolean value of $sequence is false, and it returns false, if the effective boolean value of $sequence is true.

Argument

$sequence	Description missing.

Examples

• Negate an empty sequence:

  not(())

  The result is true, since the effective boolean value of the empty sequence is false.

• Select all patients that do not have some form of angina:

  for $a in input()/patient
  let $b := $a/submitted/diagnosis
  where not(starts-with($b, "Angina"))
  return $a/name