False

False
是用以表示布尔值假的符号.

背景
背景

  • False is the symbol that represents the Boolean value false. Expressions that can be rigorously established to be false return this symbol. Examples of testing expressions that may return False include Equal, Unequal, SameQ, UnsameQ, Less/Greater/etc., Exists, and quantifier elimination via Resolve. While "Q"-functions (e.g. TrueQ, SameQ, UnsameQ) always return True or False, non-Q comparison and equality-testing functions (e.g. Equal, Unequal, Less, Greater) return unevaluated when they cannot be definitively resolved. Constructs that can be used to take a different evaluation path depending on if a condition is False or True include If, Which, and Piecewise.
  • The negation Not[False] of True is given by True. The domain consisting of False and True is denoted Booleans.
  • While TrueQ is a special case of If that yields True if an expression is explicitly True and otherwise yields False, there is no corresponding built-in function for False.

范例范例打开所有单元关闭所有单元

基本范例  (4)基本范例  (4)

计算一个布尔表达式:

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使用条件:

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测试一个构造属性:

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测试一个数学属性:

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1988年引入
(1.0)