Is there any difference in the case of variable names, function names, etc. in PHP? (example)

For those who are new to PHP, they often encounter this problem. Is PHP case-sensitive? Is php case sensitive? Are php functions case sensitive? Are PHP custom functions case sensitive? If they are distinguished, what is the impact of the distinction in case of upper and lower case? So in response to these problems, this article will give you a detailed introduction and summary of relevant knowledge points about PHP capitalization. Hope it helps friends in need.

1. PHP variables are case-sensitive

php variable name size-sensitive code examples are as follows:

As shown in the above code, we set the value of variable ABC to abc, then PHP outputs the value of ABC as abc. However, if we change the case of the variable, we will find that the result cannot be output. So remember that php variables are case sensitive!

2. Constant names are case-sensitive by default

The code example is as follows:

As above code, we define The constant value is Hello World and the output ABC value is Hello World.

Note: php.ini configuration item instructions are case-sensitive. For example, file_uploads = 1 cannot be written as File_uploads = 1

3. Method names, class names, and function names are not case-sensitive. The

is recommended to use the same name as when defined!

Code examples are as follows:

4. Magic constants are not case-sensitive

It is recommended to use uppercase! For example:

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

The code example is as follows:

In PHP, variables are stored in C language structures. Empty strings, NULL, and false are all stored with a value of 0; the type of empty strings is string, NULL. The type is NULL, false is boolean. Usually 0 and 1 equal false and true.

The above is an introduction and summary of issues related to PHP case. It has certain reference value and I hope it will be helpful to friends in need!

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