php file opearate

1. r

open the file and read only

2.r+
open the file and write

3.w
open the file and write only truncates the file to zero length.

4.w+
open the file and write truncates the file to zero length.

5.a
open the file and write ,not clip the data ,add data to end

6.a+
open the file and read ,write no clip the data, add data to end

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fopen() if open fail then return false
fclose() if close fail then return false

open the file need fou step

1. $file = fopen(filename,mode)
   2.compute filesize $filesize = filesize($file);
   3.$filedata =fread($file,$filesize);
   4.fclose($file);

<?php

/**
 * @Author: cyany_blue
 * @Date:   2018-11-24 12:16:32
 * @Last Modified by:   cyany_blue
 * @Last Modified time: 2018-11-24 12:21:36
 */
$filename = 'data.txt';
$file = fopen($filename, 'r');
if($file ==false){
	echo "open file failed";
	exit();
}else{
	$filesize = filesize($filename);
	$filetext = fread($file,$filesize);
	fclose($file);
	echo "file size:".$filesize;
	echo "<pre>$filetext</pre>";
}

fwrite

$resouce = 'data2.txt';
$file2 = fopen($resouce, 'w+');
$fileres = fwrite($file2, 'i am newly add it');
fclose($file2);
// sleep(2);
$newFile = fopen($resouce, 'r');
$newFileSize = filesize($resouce);
$content = fread($newFile, $newFileSize);
echo $content;
fclose($newFile);

Summry:
fopen need two arguments,one is filename,other is mode
fread need two arguments,one is file resource(return by fopen),other is filesize,we can use filesize($filename) to get filesize.
fwrite need two arguments ,one is file resource,other is data needed to add
fclose need one argument ,is file resource.

---

ok ,that is all .thanks.