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Home Backend Development PHP Tutorial 关于&&和or的问题、希望有实例

关于&&和or的问题、希望有实例

Jun 23, 2016 pm 02:20 PM

&& or

遇到一个问题搞了很久都不理解他的意思!想求一些案例来看下、非常新手

这两个是什么意思、如果都为真后他们下一步是怎么执行、

回复讨论(解决方案)

&& 是与的意思,就是说几个条件要同时成立才能执行下面的语句
or 是活的意思,也就是说,只要其中有一个条件或者全部条件成立就可以
@简单点就是容错的意思了

第一句,如果目录不存在,则创建目录
第二句,如果写文件失败,则输出错误信息

&& 是与的意思,就是说几个条件要同时成立才能执行下面的语句
or 是活的意思,也就是说,只要其中有一个条件或者全部条件成立就可以
@简单点就是容错的意思了

$i=1;$b=3;$ii=1;$bb=1;$i==$b && $ii==$bb;echo $i;
Copy after login
Copy after login
Copy after login

这个能不能输出$i


&& 是与的意思,就是说几个条件要同时成立才能执行下面的语句
or 是活的意思,也就是说,只要其中有一个条件或者全部条件成立就可以
@简单点就是容错的意思了

$i=1;$b=3;$ii=1;$bb=1;$i==$b && $ii==$bb;echo $i;
Copy after login
Copy after login
Copy after login

这个能不能输出$i
当然能输出,你下面的输出跟上面的那个没关系



&& 是与的意思,就是说几个条件要同时成立才能执行下面的语句
or 是活的意思,也就是说,只要其中有一个条件或者全部条件成立就可以
@简单点就是容错的意思了

$i=1;$b=3;$ii=1;$bb=1;$i==$b && $ii==$bb;echo $i;
Copy after login
Copy after login
Copy after login

这个能不能输出$i
当然能输出,你下面的输出跟上面的那个没关系
嗯、

第一句,如果目录不存在,则创建目录
第二句,如果写文件失败,则输出错误信息
这是类似一个if语句的简写吗

可以这么理解
不过 php 引入这样的过程式语句是没有道理的

可以这么理解
不过 php 引入这样的过程式语句是没有道理的
没有道理???

是的,没有道理
在一个语言中,所有的语法成分都应该符合某种风格的
像这样的过程式语句和函数式语句是否格格不入呢?
至少已经给你带来了困惑

是的,没有道理
在一个语言中,所有的语法成分都应该符合某种风格的
像这样的过程式语句和函数式语句是否格格不入呢?
至少已经给你带来了困惑
哎、

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