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File operations in PHP are nothing more than file read and write operations, deletion operations, judgment operations, permission operations and some file searches, etc. Let me post the PHP file operation functions I have learned.
File operation function
1. Get the file name: basename();
2. Get the directory where the file is located: dirname();
3. Pathinfo() obtains file information and returns an array, including the path, full name of the file, file name and extension. For example:
7. Read all the contents of the file: file() or file_get_contents(), where file() returns an array with one row of elements, and file_get_contents() returns the entire contents of the file as a String; 8. Write the file fwrite, such as:
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$handler = fopen($file, 'w'); // w will flush out the previous content, and a will append
fwrite($handler, 'content');
fclose($handler); //Remember to close the open file handle 9. There are many file reading operations,
$handler = fopen($file, 'r');
while(!feof($handler)) {
$datas[] = fgets($handler); //Read a line of content
}
while(!feof($handler)) {
$datas[] = fgetss($handler); //Read a line of content and add the html tag
}
while(!feof($handler)) {
$datas[] = fgetcsv($handler); //Read a line of content and parse the csv field
}
$content = fread($handler, $strLength); //Read the characters of the specified long read
fclose($handler);
php read file operation function
1. Use fread() to obtain
Please see the php code below:
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$file = "phpddt.txt";<🎜>
$fp = fopen($file,"r");<🎜>
if ($fp){<🎜>
while(!feof($fp)){<🎜>
//The second parameter is the read length<🎜>
$data = fread($fp, 1000);<🎜>
}<🎜>
fclose($fp);<🎜>
}<🎜>
echo $data;<🎜>
?>
Run result:
PHP Diandiantong (www.bKjia.c0m), focuses on PHP development and provides professional PHP tutorials!
2.fseek (resource handle, int offset [, int whence]), offset the pointer to offset offset.
(The content of php.txt is [Welcome to www.bKjia.c0m])
After running the following php code:
$file = "php.txt";
$fp = fopen($file,"r");
//Jump the file pointer to after the 8th byte
fseek($fp,8);
//Read data
$data = fgets($fp,4096);
echo $data;
?>
to www.bKjia.c0m
The description of whence parameter is as follows:
SEEK_SET - Set position equal to offset bytes.
SEEK_CUR - Sets the position to the current position plus offset.
SEEK_END - Set the position to the end of the file plus offset. (assignment)
If whence is not specified, the default is SEEK_SET.
3. The ftell() function is used to obtain the offset of the pointer position
The php demo code is as follows:
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$file = "phpddt.txt";
$fp = fopen($file,"r");
//Jump the file pointer to after the 8th byte
The running results are as follows:
Array
(
[web1] => Array
(
[url] => www.bKjia.c0m
[name] =>
)
[web2] => Array
(
[url] => www.baidu.com
[name] =>
)
)
Directory operations
The first introduction is a function that reads from a directory, opendir(), readdir(), closedir(). When used, the file handle is opened first, and then iteratively listed:
This is a program that returns the files and directories under the file directory (0 files will return false).
Sometimes you need to know directory information. You can use dirname($path) and basename($path) to return the directory part and file name part of the path respectively. You can use disk_free_space($path) to return the free space.
Create command:
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代码如下
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mkdir($path,0777)
mkdir($path,0777)
, 0777 is the permission code, which can be set by the umask() function under non-window conditions.
rmdir($path)
The file with the path in $path will be deleted.
dir -- directory class is also an important class for operating file directories. It has three methods, read, rewind, and close. This is a pseudo-object-oriented class. It first uses open file handles, and then uses pointers. Read., see the php manual here:
3. File Operation
● Read file
First, check whether a file can be read (permission issue), or whether it exists. We can use the is_readable function to obtain the information.:
The code is as follows
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$file = 'dirlist.php';<🎜>
if (is_readable($file) == false) {<🎜>
die('The file does not exist or cannot be read');<🎜>
} else {<🎜>
echo 'exist';<🎜>
}<🎜>
?>
The function to determine the existence of a file also includes file_exists (demonstrated below), but this is obviously not as comprehensive as is_readable. When a file exists, you can use
The code is as follows
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$file = "filelist.php";<🎜>
if (file_exists($file) == false) {<🎜>
die('File does not exist');<🎜>
}<🎜>
$data = file_get_contents($file);<🎜>
echo htmlentities($data);<🎜>
?>
However, the file_get_contents function is not supported on lower versions. You can first create a handle to the file, and then use a pointer to read the entire file:
The file_put_contents function is a newly introduced function in php5 (if you don’t know it exists, use the function_exists function to determine it first). It cannot be used in lower versions of PHP. You can use the following method:
$f = fopen($file, 'w');
fwrite($f, $data);
fclose($f);
Replace it.
When writing a file, sometimes you need to lock it, and then write:
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function cache_page($pageurl,$pagedata){
if(!$fso=fopen($pageurl,'w')){
$this->warns('Unable to open cache file.');//trigger_error
Return false;
}
if(!flock($fso,LOCK_EX)){//LOCK_NB, exclusive lock
$this->warns('Unable to lock cache file.');//trigger_error
Return false;
}
if(!fwrite($fso,$pagedata)){//Write byte stream, serialize to write other formats
$this->warns('Unable to write to cache file.');//trigger_error
Return false;
}
flock($fso,LOCK_UN);//Release lock
fclose($fso);
return true;
}
● Copy and delete files
Deleting files in PHP is very easy. Use the unlink function to simply operate:
The code is as follows
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$file = 'dirlist.php';<🎜>
$result = @unlink ($file);<🎜>
if ($result == false) {<🎜>
echo 'The mosquitoes were driven away';<🎜>
} else {<🎜>
echo 'Can't get rid';<🎜>
}<🎜>
?>
That’s it.
Copying files is also easy:
The code is as follows
代码如下
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$file = 'yang.txt';
$newfile = 'ji.txt'; # 这个文件父文件夹必须能写
if (file_exists($file) == false) {
die ('小样没上线,无法复制');
}
$result = copy($file, $newfile);
if ($result == false) {
echo '复制记忆ok';
}
?>
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$file = 'yang.txt';
$newfile = 'ji.txt'; # The parent folder of this file must be writable
if (file_exists($file) == false) {
die ('The demo is not online and cannot be copied');
?>The returned timestamp is the unix timestamp, which is commonly used in caching technology.Related are also the time fileatime() and filectime() are used to obtain the last time accessed $owner = posix_getpwuid(fileowner($file));(non-window system), ileperms() obtains file permissions,
The code is as follows
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$file = 'dirlist.php';<🎜>
$perms = substr(sprintf('%o', fileperms($file)), -4);<🎜>
echo $perms;<🎜>
?>
filesize() returns the file size in bytes:
The code is as follows
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<🎜>// Output is similar: somefile.txt: 1024 bytes<🎜>
<🎜>$filename = 'somefile.txt';<🎜>
echo $filename . ': ' . filesize($filename) . ' bytes';<🎜>
<🎜>?>
To get all the information of a file, there is a function stat() function that returns an array:
The code is as follows
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$file = 'dirlist.php';<🎜>
$perms = stat($file);<🎜>
var_dump($perms);<🎜>
?>
http://www.bkjia.com/PHPjc/632695.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/632695.htmlTechArticleFile operations in php are nothing more than file read and write operations, deletion operations, judgment operations, permission operations and some files Search and so on, let me introduce the php file operation functions I learned...
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