The fgets() function in PHP is used to read the file content line by line

The fgets() function in PHP is used to read the contents of the file line by line

In PHP, we often need to read the contents of the file. When the file content is large, reading the entire file into memory at one time may cause memory overflow problems. To avoid this, we can process the file contents by reading the file line by line.

In PHP, the fgets() function is a function used to read the contents of a file line by line. Its syntax is as follows:

string fgets ( resource $handle [, int $length ] )

Among them, $handle represents the file pointer, which is the resource object returned after opening the file, $length represents the number of bytes to be read, and the default is 1024.

Next, I will demonstrate the use of the fgets() function through a specific code example.

First, we prepare a text file named "example.txt" with the following content:

Hello World!
This is an example file.
I am learning PHP.

Next, we use PHP code to open the file and read the file content line by line ：

<?php
$file = fopen("example.txt", "r");
if ($file) {
    while (($line = fgets($file)) !== false) {
        echo $line;
    }
    fclose($file);
} else {
    echo "文件打开失败！";
}
?>

In the above code, we first use the fopen() function to open the file and save the returned file pointer to the variable $file. The first parameter "example.txt" represents the file name to be opened, and the second parameter "r" represents opening the file in read-only mode.

Next, we use the fgets() function to read the file content line by line through a while loop and save it to the variable $line. When the fgets() function returns false, it means that the end of the file has been reached and the loop ends.

Finally, we use the fclose() function to close the file.

Run the above code, we can see the following output:

Hello World!
This is an example file.
I am learning PHP.

This is an example of reading the file content line by line through the fgets() function.

It should be noted that the fgets() function can only read one line of content at a time. If the file content is too long, you may need to call the fgets() function multiple times to read the complete file content.

In addition, you can control the number of bytes read each time by specifying the $length parameter. If the $length parameter is not specified, the default is 1024 bytes.

To summarize, you can easily read files line by line through the fgets() function. This reading method can avoid the problem of memory overflow caused by reading the entire file at once, and is suitable for processing large files. I hope the content of this article will help you understand the fgets() function in PHP.

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