Instructions for using fopen function to open, create and read PHP files_PHP tutorial

This article introduces a simple file operation function fopen. The fopen function can open, read, and assist in file saving. Let me summarize the operation of PHP files. ​

Open file

The simplest syntax of fopen is as follows:

fopen(filepath,mode)

Here is an example of PHP code to open a file:

The code is as follows	Copy code
代码如下 复制代码 $f = fopen("c:datainfo.txt", "r"); ?> $f = fopen("c:datainfo.txt", "r"); ?>

Among them, c:datainfo.txt is the file path, and r indicates that the mode of opening the file is read only mode.

Describes how to use PHP built-in function fclose to close a file.

The fclose function syntax is as follows:

fclose(filepointer)

代码如下	复制代码
$f = fopen("c:datainfo.txt", "r"); fclose($f); ?>

If successful, the fclose function returns TRUE, if failed, the fclose function returns FALSE.

Here is a PHP code example of the fclose function:

The code is as follows	Copy code
$f = fopen("c:datainfo.txt", "r"); fclose($f); ?>

fwrite writes file

fwrite function.
PHP built-in function fwrite is used to write files.

The common syntax of the fwrite function is:

fwrite(handle,string)
Among them, the parameter handle represents the file pointer resource (usually created by the fopen function), and string represents the content to be written.

代码如下	复制代码

The following PHP code example demonstrates how to create a new file, write its contents, then save and close the file:

$f= fopen("C:blablaphpwrite.txt","w");

代码如下	复制代码
$f= fopen("C:blablaphpwrite.txt","a");

fwrite($f,"It is awesome."); fclose($f);echo "done"; ?>

The code is as follows	Copy code

After executing the PHP file, a file with the path C:blablaphpwrite.txt will be created. The content of the file is It is awesome. If you want to append content to the existing file, you only need to modify the parameter mode value of fopen, as follows:

The code is as follows	Copy code
$f= fopen("C:blablaphpwrite.txt","a");

For the parameter mode value of the fopen function, see fopen for details.

The fwrite function returns the number of bytes written to the file. If an error occurs, it returns FALSE.

fgets reads a line of file

Use the PHP built-in function fgets to read a line of a file.

The syntax for fgets to read a line of file content is:

fgets(filepointer)

Let’s give an example below to describe how to read a file line by line.

Suppose we have a sites.txt file with three lines and the following content:

woyouxian.comblabla.cngoogle.com
The file path of sites.txt is:

C:blablaphpsites.txt
We use PHP to read the file content line by line. The PHP code is as follows:

$f= fopen("C:blablaphpsites.txt","r");
while (!feof($f))
{
$line = fgets($f);
echo "site: ",$line,"
";
}fclose($f);
?>

代码如下	复制代码

Execute the PHP file and the displayed result returned is:

site: woyouxian.comsite: blabla.cnsite: google.com

The first line of this PHP code opens a file, and the last line closes a file. The while loop statement means that when the file does not end, read one line and execute it in a loop until the file pointer reaches the end of the article.

The feof function is a built-in function of PHP, used to test whether the file pointer has reached the end of the file. Returns TRUE if yes, FALSE if not. The English meaning of eof is end of file, which is easy to remember.

Under normal circumstances, the return value of the fgets function is a string. If an error occurs, it returns FALSE