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java软件工程师学php - 5. 变量的“状态”

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Release： 2016-06-13 13:08:42
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java程序员学php - 5. 变量的“状态”
isset($a): 判断一下这个变量是否已经定义

unset($a): destroy a variable

Related labels：
isset java unset variable
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