How to read and write files in php

PHP method of reading and writing files

<?php  
//生成HTML  
$countfile="template.html";  
$num=file_get_contents($countfile);  
echo $num;  
$num=str_replace("|*|*|PAGE_TITLE|*|*|","myhome",$num);  
$path="template.html";  
$handle=fopen($path,"w"); //写入方式打开新闻路径  
fwrite($handle,$num); //把刚才替换的内容写进生成的HTML文件  
fclose($handle);  
?>  
file_get_contents -- 将整个文件读入一个字符串
file -- 把整个文件读入一个数组中

In PHP website development, there are usually two ways to store data, one is stored in text files, such as txt files , one is to store in database, such as Mysql. Compared with database storage, file storage has no advantages, but file reading and writing operations are still used from time to time in basic PHP development. Today I will share with you how to use PHP technology to implement files. The file writing operation tutorial of reading and writing can also be regarded as an introductory study of PHP file reading and writing operations.
The operation of writing data to a file mainly involves three steps and some file operation functions are as follows:
1. Open the file (file operation function: fopen)
2. Write the file (file operation function: fwrite etc.)
3. Close the file (file operation function: fclose)
The following will explain through the file reading and writing operation code example tutorial
Basic PHP file writing operation function fopen, fwrite, fclose application tutorial

<? 
@$fp = fopen("leapsoulcn.txt","w"); 
if(!$fp){ 
echo "system error"; 
exit(); 
}else { 
$fileData = "domain"."\t"."www.leapsoul.cn"."\n"; 
$fileData = $fileData."description"."\t"."PHP网站开发教程网，面向PHP初学者的PHP教程网。"."\n"; 
$fileData = $fileData."title"."\t"."本文主要讲述PHP文件读写操作中最基本的文件写入教程。"; 
fwrite($fp,$fileData); 
fclose($fp); 
} 
?>

Comment: In this file reading and writing operation example code, the main function is to write two lines of text to the file.
Knowledge points:
1. Use the fopen function to open a file. When applying the fopen function to prepare to open a file, you first need to clarify:
What to open the file for? Is it reading the data in the file, writing the data to the file, or reading and writing the file?
In addition, you need to consider if relevant data already exists in the file, should you overwrite the data in the original file, or just add new data to the end of the file
These issues involve fopen in PHP file read and write operations For the application of file mode in the function, the fopen function prototype is as follows:

fopen(filename,mode,include_path,context)

When calling the file operation function fopen(), you usually need to pass two or three parameters.
　filename: Specifies the file or URL to be opened. You can specify the absolute path of the file, which is generally C:\ for Windows and / for Unix. You can also open remote files through the URL. The file written here is in the same directory as the PHP file writing code file I placed.
Mode: Specifies the type of access required to the file/stream. That is, the mode in which the file is opened.
include_path: optional. If you need to search for files in include_path, you can set this parameter to 1 or TRUE.
Description of commonly used fopen file operation modes
"r" - Open the file in read-only mode and start reading from the file header.
　"r+" - Open the file in read and write mode.
　"w" - Open the file for writing and start writing from the beginning of the file. If the file does not exist, try to create it. If the file exists, delete the contents of the file first.
　"w+" - Open the file for reading and writing, starting from the beginning of the file. If the file does not exist, try to create it. If the file exists, delete the contents of the file first.
　"a" - Open for writing, append writing starting from the end of the file. If the file does not exist then attempts to create it.
　"a+" - Open in read-write mode, append writing or reading starting from the end of the file. If the file does not exist then attempts to create it.
Note: When performing file read and write operations, you must ensure that the file you open has the corresponding read and write permissions, otherwise fopen will report an error. You can use @ to suppress errors and then handle them appropriately.
　2. After using the file operation function fopen to open the file, you need to assign a value to the variable and then write it to the file pointer pointed to by $fp. In the above example of the PHP file writing operation tutorial, I used line by line. Storage, that is, newline storage, mainly uses \n as the newline separator.
The fwrite file writing function prototype is as follows:

fwrite(fp,string,length)

在这里你也可以使用文件写入函数fputs，其是fwrite的别名函数，功能与用法与fwrite一样。 

　　在文件写入函数fwrite中length是可选项，主要用来设定写入文件的最大字符数，如果设定了这个参数，fwrite会按设定的length，在指定文件中写入规定长度的字符。fwrite()返回写入文件的字符数，出现错误时则返回false。 

　　在文件写入操作完成后，需要关闭文件句柄，否则会占用系统资源等。可以使用fclose($fp)函数来完成这件事。文件关闭成功则返回true，否则返回false。 

　　至此文件写入操作就完成了。 

　　以上是PHP文件读写操作教程之文件写入操作的最基本应用，除了文件写入操作，在PHP网站开发中经常需要读取相关的文件内容，文件读写操作函数中可以使用不同的函数实现对文件的读操作。下次将分下如何读取文件。

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