variant_add
Description
mixed variant_add ( mixed left, mixed right )Adds left to right using the following rules (taken from the MSDN library), which correspond to those of Visual Basic:
表格 1. Variant Addition Rules
| If | Then |
|---|---|
| Both expressions are of the string type | Concatenation |
| One expression is a string type and the other a character | Addition |
| One expression is numeric and the other is a string | Addition |
| Both expressions are numeric | Addition |
| Either expression is NULL | NULL is returned |
| Both expressions are empty | Integer subtype is returned |
See also variant_sub().
注: 對於所有的變量算法函數，此函數的參數可以要麼是 PHP 自身的類型（整型，字串，浮點型，布爾型或是 NULL），要麼是一個 COM，VARIANT 或 DOTNET 類的案例。PHP 自身類型將被轉換為變量，使用與 VARIANT 類的構造函數中相同的規則。COM 和 DOTNET 物件將具有其預設屬性的值，取得並作為變量值使用。
變量算法函數是 COM 庫中與其名稱接近的函數的封裝。此類函數的更多訊息請參考 MSDN 庫。PHP 函數命名有少許不同，例如 PHP 中的 variant_add() 對應於 MSDN 文件中的 VarAdd()。