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PHP Tutorial
Summary of usage examples of functions for reading files in PHP
Summary of usage examples of functions for reading files in PHP
Recently sorted out several common ways to read files in PHP and paid attention to some codes, as follows:
You can use fopen and ## to read files in PHP #file_get_contentsThere is no essential difference between these two functions, except that the php code for reading files in the former is a little more complicated than the latter.
<?php
$file_name = "1.txt";
echo $file_name . "";
$fp = fopen($file_name, 'r');
//$buffer=fgets($fp);
while (!feof($fp)) {
$buffer = fgets($fp);
echo $buffer;
}
fclose($fp);
?>1.fread
string fread ( int $handle , int $length )
fread( ) reads up to length bytes from the file pointed to by handle. This function is called after reading up to length bytes, or when EOF is reached, or (for network streams) when a packet is available, or (after opening a user space stream) 8192 bytes have been read. Will stop reading the file, depending on which condition is encountered first. fread() returns the string read, or FALSE if an error occurs.<?php $filename = "/usr/local/something.txt"; $handle = fopen($filename, "r");//读取二进制文件时，需要将第二个参数设置成'rb' //通过filesize获得文件大小，将整个文件一下子读到一个字符串中 $contents = fread($handle, filesize ($filename)); fclose($handle); ?>
<?php
$handle = fopen('http://www.baidu.com', 'r');
$content = '';
while(!feof($handle)){
$content .= fread($handle, 8080);
}
echo $content;
fclose($handle);
?><?php
$handle = fopen('http://www.baidu.com', 'r');
$content = '';
while(false != ($a = fread($handle, 8080))){//返回false表示已经读取到文件末尾
$content .= $a;
}
echo $content;
fclose($handle);
?>2.fgets
string fgets ( int $handle [, int $length ] )
fgets() reads a line from the file pointed to by handle and returns a string with a length of at most length - 1 byte. Stops when a newline character (included in the return value), EOF, or length - 1 bytes has been read (whichever occurs first). If length is not specified, it defaults to 1K, or 1024 bytes.<?php
$handle = fopen('./file.txt', 'r');
while(!feof($handle)){
echo fgets($handle, 1024);
}
fclose($handle);
?>3.fgetss
string fgetss ( resource $handle [, int $length [, string $allowable_tags ]] )
Same function as fgets, but fgetss will try to remove any HTML and PHP tags from the read text. You can use the optional third parameter to specify which tags are not to be removed.<?php
$handle = fopen('./file.txt', 'r');
while(!feof($handle)){
echo fgetss($handle, 1024, '<br>');
}
fclose($handle);
?>4.file
array file ( string $filename [, int $use_include_path [, resource $context ]] )
<?php
$a = file('./file.txt');
foreach($a as $line => $content){
echo 'line '.($line + 1).':'.$content;
}
?>5.readfile
Read a file and write it to the output buffer. Returns the number of bytes read from the file. If an error occurs, FALSE is returned and an
error message is displayed unless called as @readfile(). <?php
$size = readfile('./file.txt');
echo $size;
?>
file_get_contents##string file_get_contents ( string $filename [, bool $use_include_path [, resource $context [, int $offset [, int $maxlen ]]]] )
Read the file into a string. The third parameter $context can be used to set some parameters, such as setting timeout when accessing remote files, etc.
In addition, file_get_contents has much better performance than the above functions, so file_get_contents should be given priority. But readfile seems to have better performance than file_get_contents (?), because it does not need to call fopen.<?php
$ctx = stream_context_create(array(
'http' => array(
'timeout' => 1 //设置超时
)
)
);
echo file_get_contents("http://www.baidu.com/", 0, $ctx);
?>7.fpassthru
int fpassthru ( resource $handle )
Change the given file pointer from the current The position is read to EOF and the result is written to the output buffer.
<?php
header("Content-Type:text/html;charset=utf-8");
$handle = fopen('./test2.php', 'r');
fseek($handle, 1024);//将指针定位到1024字节处
fpassthru($handle);
?>8.parse_ini_file
##array parse_ini_file ( string $filename [, bool $process_sections ] )
parse_ini_file() loads an ini file specified by filename and returns its settings as an associative array. If you set the final process_sections parameter to TRUE, you will get a multidimensional array, including the name and settings of each section in the
config file. The default value for process_sections is FALSE. Notice:
1. If the value in the ini file contains any non-alphanumeric characters, it needs to be enclosed in double quotes (").
2. Some reserved words cannot be used as key names in the ini file, including: null, yes, no, true and false. The values null, no and false are equivalent to "", and the values yes and true are equivalent to "1". The characters {}|&~
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