What are the methods and functions for reading file contents in php?

There are many ways for php to read the contents of files. Here are some commonly used functions for reading files.

First type:

<?php
$file_path = "test.txt";
if(file_exists($file_path)){
$fp = fopen($file_path,"r");
$str = fread($fp,filesize($file_path));//指定读取大小，这里把整个文件内容读取出来
echo $str = str_replace("\r\n","<br />",$str);
}

Analysis: The fopen() function opens a file or URL.

Second type:

<?php
$file_path = "test.txt";
if(file_exists($file_path)){
$str = file_get_contents($file_path);//将整个文件内容读入到一个字符串中
$str = str_replace("\r\n","<br />",$str);
echo $str;
}
?>

Analysis: The file_get_contents() function reads the entire file into a string.

Third type:

<?php
$file_path = "test.txt";
if(file_exists($file_path)){
$fp = fopen($file_path,"r");
$str = "";
$buffer = 1024;//每次读取 1024 字节
while(!feof($fp)){//循环读取，直至读取完整个文件
$str .= fread($fp,$buffer);
} 
$str = str_replace("\r\n","<br />",$str);
echo $str;
}
?>

Analysis: The fread() function reads the maximum number of bytes; the feof() function checks whether the end of the file has been reached.

Fourth:

<?php
$file_path = "test.txt";
if(file_exists($file_path)){
$file_arr = file($file_path);
for($i=0;$i<count($file_arr);$i++){//逐行读取文件内容
echo $file_arr[$i]."<br />";
}
/*
foreach($file_arr as $value){
echo $value."<br />";
}*/
}
?>

Analysis: The file() function reads the entire file into an array.

Fifth type:

<?php
$file_path = "test.txt";
if(file_exists($file_path)){
$fp = fopen($file_path,"r");
$str ="";
while(!feof($fp)){
$str .= fgets($fp);//逐行读取。如果fgets不写length参数，默认是读取1k。
}
$str = str_replace("\r\n","<br />",$str);
echo $str;
}
?>

Analysis: The fgets() function returns a line from the open file.

The above introduces several functions for reading file content, for your reference only.

For more related questions, please visit the PHP Chinese website: PHP Video Tutorial

The above is the detailed content of What are the methods and functions for reading file contents in php?. For more information, please follow other related articles on the PHP Chinese website!