What does var_dump mean in php?

"var_dump" is a debugging function in PHP, used to determine the type and length of a variable and output the value of the variable. Use var_dump to print all objects, and you can view the data structure inside the object; the variables in var_dump must exist.

var_dump is a debugging function in PHP. You can use var_dump to print all objects and view the data structure inside the object.

The meaning of var_dump in PHP is to determine the type and length of a variable and output the value of the variable.

var_export must return legal PHP code. In other words, the code returned by daovar_export can be directly assigned to a variable as PHP code. The variables in var_dump Must exist.

Extended information

1. If the variable has a value, the value of the variable is lost and the data type is returned. This function displays structural information about one or more expressions, including the expression's type and value. Arrays will expand values ​​recursively, showing their structure through indentation.

2. The variables in var_dump must exist. If the variable exists but the value is empty, it will return false; if there is no variable, it will return NULL. It has its own output function. No need to add other output functions.

3. var_export must return legal PHP code. In other words, the code returned by var_export can be directly assigned to a variable as PHP code. And this variable will get the same type of value as var_export.

4. PHP (foreign name: PHP: Hypertext Preprocessor, Chinese name: "Hypertext Preprocessor") is a general open source scripting language. The syntax absorbs the characteristics of C language, Java and Perl, which is easy to learn and widely used. It is mainly suitable for the field of Web development.

5. PHP can execute dynamic web pages faster than CGI or Perl. Compared with other programming languages, dynamic pages made with PHP embed programs into HTML documents for execution, and the execution efficiency is much higher than CGI that completely generates HTML tags; PHP can also execute compiled code, and the compilation can Achieve encryption and optimize code running, making the code run faster.

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