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Is php case sensitive?

青灯夜游
青灯夜游 Original
2019-10-11 15:09:19 4197browse

In the process of developing PHP, because naming case issues can easily lead to code errors, we have compiled some information on PHP case sensitivity from the Internet. Friends who need it can refer to it.

Is php case sensitive?

PHP’s handling of case-sensitive issues is messy, and problems may occasionally occur when writing code, so I’ll summarize it here. But I'm not encouraging everyone to use these rules. It is recommended that everyone always adhere to "case sensitivity" and follow unified coding standards.

1. Variable names are case-sensitive


      

2. Constant names are case-sensitive by default and are usually written in uppercase

Constants defined using define are case-sensitive.

3. Function names, method names, and class names are not case-sensitive

But it is recommended to use the same name as when defined


      

show (); //Output Hello World. Recommended writing method

SHOW(); //Output Hello World


      

4. Magic constants are not case-sensitive. Capital letters are recommended

Includes: __LINE__, __FILE__, __DIR__, __FUNCTION__, __CLASS__, __METHOD__, __NAMESPACE__.


      

5. NULL, TRUE and FALSE are not case-sensitive


      

5. Array index (key name) is case-sensitive

'first'); echo $arr['one']; //输出'first' echo $arr['One']; //无输出并报错 echo $Arr['one']; //上面讲过,变量名区分大小写,所以无输出并报错 ?>

Summary:

In PHP, function names, method names, class names, and keywords are not case-sensitive; but variables Names and constant names are case-sensitive.

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