Commonly used functions for reading local files in PHP (fopen and file_get_contents)_PHP tutorial

Below we use .txt file as an example to introduce the function of PHP to read local files. To read files, we can use fopen or file_get_contents to read. File_get_contents is simpler, but fopen requires the cooperation of fread to display the read content.

1. First, let’s introduce the fopen() function

Below we give a code demo that directly opens a local file. We have added the necessary places. Commented:

Copy code The code is as follows:

//Example code to directly open a local file
//Suppose our local file is a text named xmlas.txt
$filedemo = "xmlas.txt";
$fpdemo = fopen($filedemo,"r");
if ($fpdemo){
while(!feof($fpdemo)){
//Number of characters read by 1000
$datademo = fread($fpdemo, 1000);
}
fclose($fpdemo);
}
echo $datademo;
?>

2. Use the file_get_contents() function to output the entire file in a string:

Suppose there is such a sentence in our xmlas.txt text file: Movies are getting better and better now. There is less and less passion. If you want to have all the orgasms, please watch Japanese Love

Action movie!
Then the example code of our file_get_contents() function is as follows:

Copy code The code is as follows:

echo file_get_contents("xmlas.txt");
//The output content at this time is the content in xmlas.txt:
//Today’s movies are becoming less and less passionate. If you want to have all the climax, please watch Japanese love action movies!
?>

3. How to read a local folder instead of a separate file:
Please see the example code below, in which we will read a folder named xmlas:

Copy code The code is as follows:

$dirdemo = opendir('/xmlas');
while(($filedemo = readdir($dirdemo))!=false){
if ($filedemo!="." && $filedemo!="..") {
$nsdemo = explode ('.', $filedemo);
echo $nsdemo[0];
} }
}
closedir($dirdemo);
?>

4. We can also use fopen to write files

Copy code The code is as follows:

/**
*Write file using fopen
*@param string $filename
*@param string $contents
*@return boolean
*/

function wirte($ filename,&$contents)
{
$fp=fopen($filename,"wb");
if($fp)
{
flock($fp,LOCK_EX);/ /Lock the file at the same time, only one person can operate it
fwrite($fp,$contents);
flock($fp,LOCK_UN);//Save the data to unlock the file and save it
fclose($ fp);
return true;
}else
{
return false;
}
}

In this way, I only need to use fopen and fwrite to read and write files.

Note: lOpen the file

Before opening a file, we need to know the path of the file and whether the file exists.

Use the $_SERVER["DOCUMENT_ROOT"] built-in global variable to obtain the relative path of the site. As follows:

Copy code The code is as follows:

$root = $_SERVER[“DOCUMENT_ROOT”];

in Use the function file_exists() to check whether the file exists. As follows:

Copy code The code is as follows:

If(!file_exists("$root/order.txt")){echo 'File does not exist';}

This may be more reasonable and practical.

http://www.bkjia.com/PHPjc/313644.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/313644.htmlTechArticle Below we use .txt file as an example to introduce the function of php to read local files. To read files, we can use fopen or file_get_contents to read, file_get_contents is simpler and fopen requires...