Summary of five methods for reading files in PHP

<?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);
}
?>

<?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;
}
?>

<?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;
}
?>

<?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 />";
 }*/
}
?>

<?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;
}
?>