PHP循环块内需要的变量，定义在循环外面好还是循环里面？
如题，定义在循环内部是不是每次循环都新建一个变量？
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不好说，看你的需求吧
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这个看你的需求了，如果想变量可以改变值，循环到下一次可以接着用，放在外面，如果只是每个循环体内有效，就放在内部。
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能放在外面就不放在里面
能放在外层就不放在里层
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还是那句话，如果要多次使用，而且变量值不改变的话，建议放到外面。 如果仅仅是在一个循环体内使用而且值可能会改变的话就放到里面。
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个人愚见：变量使用完之后记得unset掉就好，不用在乎里面外面。
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赞同楼上，不unset也可以。 既然变量值不一样，那么无论放到哪，只要在每次使用前，重新给该变量赋值就可以了。不用纠结放在里面还是外面。
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根据需求来放的了，如果放在循环体外，循环期间变量都不会变化；如果放在循环体内，循环体内，循环期间变量会发生变化
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定义在循环体外面，每次在循环体中使用完后，再将其初始化为原始状态
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