Questions and answers about file operations in PHP dynamic website production_PHP tutorial

Foreword:

PHP supports the operations of various databases, and it also has rich operating methods for file operations. Many friends’ current operations are still based on file operations, but sometimes there are still a lot of confusions and doubts when operating files. , the following is a collection of some problems about file operations that I encountered in my daily writing process and that my friends on the forum encountered.

Question: How to create a new file?

Answer:

1. Use fopen (file name to be created, parameters), the parameters can be w,w,a,a

2. Use exec(echo '' > the file name to be created); this is to use the system method to create the file. You can also use the touch Linux command to create

Question: Why can't I create the file?

Answer:

1. If you use fopen to create a file, do you use the parameters correctly

2. For system permission issues, please ask your WEBMASTER whether your FTP directory has write permission

3. FTP permissions issue, you need to confirm that the directory where the file where your PHP file is to be written must have write permission, that is, the other group must have write permission after logging in to your FTP software,
If not, please modify the permissions and try

Question: How to read a file into an array?

Answer: Use the file function

Question: How to read out all files?

Answer:

1. Use fread($fp);

2. If your PHP version >=4.3.0, you can use file_get_contents();

Question: How to determine whether a file exists?

Answer: Use file_exists();

Ask again: Why not use fopen() to determine?

Answer: The reason is that sometimes the data returned by fopen leads us to wrong judgments due to permission issues

Question: Why do I get an error when I read a WEB page?

Answer:

1. It may be that your passed parameters are wrong. When reading a WEB page, you can only use r mode to read the page

2. Make sure the WEB page you want to read is accessible

Question: How can I get the relevant attributes of a file?

Answer: PHP provides a set of methods to obtain file attributes, such as filemtime(), fileowner(), filegroup(), filectime(), fileatime()... Please refer to the manual for specific usage.

Question: After opening a file in PHP, can the file "cursor" be positioned like C?

Answer: Yes, use fseek();

Question: I want to prevent others from accessing the file when accessing it. What should I do?

Answer:

1. You can use other procedures to restrict users from accessing pages for file operations

http://www.bkjia.com/PHPjc/632438.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/632438.htmlTechArticleForeword: PHP has support for various database operations, and also has rich operations for file operations. Method, many friends’ current operations are still based on file operations, but sometimes...