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  • variant_add()

    (PHP 5, PHP 7)

    "Adds" two variant values together and returns the result

    说明

    variant_add(mixed $left, mixed $right): variant

    Adds$leftto$rightusing the following rules(taken from the MSDN library), which correspond to those of Visual Basic:

    Variant Addition Rules
    IfThen
    Both expressions are of the string typeConcatenation
    One expression is a string type and the other a characterAddition
    One expression is numeric and the other is a stringAddition
    Both expressions are numericAddition
    Either expression is NULLNULL is returned
    Both expressions are emptyInteger subtype is returned

    参数

    $left

    The left operand.

    $right

    The right operand.

    Note:

    对于所有变量运算函数,本函数的参数可以是 PHP 内置的类型(整数,字符串,浮点数,布尔型或者NULL),或者是一个 COM,VARIANT 或者 DOTNET 类的实例。PHP 内置类型将会使用和构造VARIANT类相同的规则转换成变量。COM 和 DOTNET 对象的值将会取其默认属性并被当成变量值使用。

    变量运算函数是同名函数在 COM 库中的外包;有关此类函数的更多信息参见 MSDN 库。PHP 函数命名有少许区别,例如 PHP 中的variant_add()对应于 MSDN 文档中的VarAdd()

    返回值

    Returns the result.

    错误/异常

    Throws a com_exception on failure.

    参见

    • variant_sub()Subtracts the value of the right variant from the left variant value

    上篇:variant_abs()

    下篇:variant_and()