Network Security Internet Technology Development Database Servers Mobile Phone Android Software Apple Software Computer Software News IT Information

In addition to Weibo, there is also WeChat

Please pay attention

WeChat public account

Shulou

What does a null value in php mean?

2025-04-03 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Development >

Share

Shulou(Shulou.com)06/02 Report--

Editor to share with you what the null value of php refers to. I hope you will get something after reading this article. Let's discuss it together.

Php null refers to the null data type, indicating that a variable does not have any value; null values are case-insensitive, that is, null is the same as NULL or Null.

This article operating environment: windows7 system, PHP7.1 version, DELL G3 computer

What does a null value of php mean?

Php: null value (null) data type

Null value (null):

A null value, like its name, indicates that a variable does not have any value. Null values (null) are case-insensitive, meaning that null is the same as NULL or Null.

There are three situations in which null values are assigned in PHP:

The first kind:

Has not been assigned yet

The second kind:

Is assigned to NULL.

The third kind:

Variables processed by the unset () function

Example

The string string1 is assigned to null,string2 with no declaration and assignment at all, so output null, and the final string3, though given an initial value, becomes null after being processed by the unset () function. The function unset () removes variables from memory. The code is as follows:

The is_null function is used to determine whether the variable is null. As we will talk about later, this function returns a Boolean. If the variable is null, it returns true, otherwise it returns false. The unset () function is used to destroy known variables.

After reading this article, I believe you have a certain understanding of "what is the meaning of php null". If you want to know more about it, you are welcome to follow the industry information channel. Thank you for reading!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.

Views: 0

*The comments in the above article only represent the author's personal views and do not represent the views and positions of this website. If you have more insights, please feel free to contribute and share.

Share To

Development

Wechat

© 2024 shulou.com SLNews company. All rights reserved.

12
Report