什么是PHP语言构造
什么是PHP语言结构？
初学PHP我看到有地方说echo，die 都是PHP语言结构。
谁能说得形象一点，让我加深对PHP的理解。
非常感谢
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说实在的，你不需要把它搞清楚，只要记住他们 是没有返回值的，不能用于需要返回值的场合 就可以了
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语言结构 函数
大多数没有返回值 可以有也可以没有返回值
大部分可以以语句方式使用 必须以函数方式调用
大多是关键字 不是关键字
大多有对应的opcode 没有opcode
源码中不是PHP_FUNCTION宏来定义 源码中以PHP_FUNCTION宏定义
就是说语言结构是php语法的组成部分
函数只是函数......
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语言结构其实就是php的本源,涉及到的内容很少,常见的有:顺序,分支,循环
例如你提到的echo die之类的另外还有if else break等.
其实概念你可以不必那么在意,只需要知道这个语句怎么用,在什么场合下使用就好了
因为将来你在写程式的时候没有人会在乎你用的是语言结构或是函数,大家要的基本上都是最终结果.
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同意楼上的观点
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说白了就是php的系统关键字就是php的语言结构.常见的也是易混淆的有,echo,print,array,die,isset,unset,empty,require,list,empty记住这些面试足够了!
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