File operation has always been a headache for web programmers, and file operation is a must in systems like CMS. Nowadays, the functions of PHP file operation are already very powerful, and this part of the file is also a very important part of learning PHP. I hope everyone will not ignore it. This article will briefly introduce several basic file operations of PHP, and finally comes with a summary of PHP file functions for your reference and learning.
1. Open the file: fopen("file name","mode");
Mode parameters:
r: Read-only, point the file pointer to the file header.
r+: read/write, point the file pointer to the file header.
w: Write only, open and clear the contents of the file. If the file does not exist, create the file.
w+: read/write, open and clear the contents of the file. If the file does not exist, create the file.
a: Append, open and write to the end of the file. If the file does not exist, a new file is created.
a+: Read/append, keep the file content by writing content to the end of the file.
2. Close the file: fclose();
After using the file, you should explicitly tell PHP that the file has been used, for example:
$file=fopen("","r"); //Close an open file pointer
//some code be executed
fclose=($file);
3. Check whether the end of the file has been reached: feof();
For example: if(feof($file)){ echo "end of file";}
4. Read the file line by line: fgets();
For example:
$file=fopen("","r");
while(!feof($file)){
echo fgets($file)."< br/>";
}
fclose($file);
5. Read the file character by character: fgetc()
6. Read any binary data: fread()
7. Determine the status of file reading
Each file handle has a file pointer. According to the mode parameter of the fopen function, the file pointer is initially at the beginning of the file or at the end of the file. feof() can determine whether the file has reached the end; the filesize() function returns the file size.
8. Write files and permission judgment
fwrite() function executes file writing
is_readable()//Judge whether the file is readable
is_writeable()//Determine whether the file is writeable
is_writable()//Judge whether the file is writable
file_exists()//Is this file present?
Example code:
$filename = '';
$somecontent;
// First we need to confirm that the file exists and is writableif (is_writable($filename)) {
// In this example, we will use the Add mode to open $filename, so the file pointer will be at the beginning of the file, which is where the $somecontent will be written when we use fwrite().
if (!$handle = fopen($filename, 'a')) {
echo "Cannot open file $filename";
exit;
}
// Write $somecontent to the file we opened. if (fwrite($handle, $somecontent) === FALSE) {
echo "Cannot write to file $filename";
exit;
}
echo "Successfully written $somecontent to file$filename";
fclose($handle);
}
else{
echo "File $filename is not writable";
}
9. Read the file to an array:
$array=file(""), $array[0] is the first line of text, and so on. If you want to flip the entire array, for example:
$arr=array_reverse($array);
Then the last line of text is $arr[0]
10. Access the directory
It is recommended to use forward slash "/" for directory access, which is compatible with Windows and Unix systems. The main functions include:
basename()//Returns the file name that does not include path information
dirname()//Returns the directory part of the file name
realpath()//Accept the relative path and return the absolute path of the file
pathinfo()//Extract the directory name, base file name and extension of the given path
opendir()//Open the directory and return the resource handle
readdir()//Read directory items
rewinddir()//Return the read pointer to the beginning
closedir()//Close the read handle
chdir()//Change the current working directory during the execution of the current script
mkdir()//Create directory
rmdir() deletes directory
Attachment: Complete collection of PHP file functions
basename — Returns the file name part in the path
chgrp — Change the group to which the file belongs
chmod — Change file mode
chown — Change the owner of the file
clearstatcache — Clear file status cache
copy — copy file
delete — see unlink() or unset()
dirname — Returns the directory part in the path
disk_free_space — Returns the available space in the directory
disk_total_space — Returns the total disk size of a directory
diskfreespace — an alias for disk_free_space()
fclose — Close an open file pointer
feof — tests whether the file pointer reaches the end of the file
ffflush — output buffered content to a file
fgetc — Read characters from file pointer
fgetcsv — read a line from a file pointer and parse the CSV field
fgets — read a line from a file pointer
fgetss — read a line from a file pointer and filter out HTML tags
file_exists — Check if the file or directory exists
file_get_contents — reads the entire file into a string
file_put_contents — Write a string to a file
file — read the entire file into an array
fileatime — Get the last access time of the file
filectime — This PHP file function gets the inode modification time of the file
filegroup — the group to obtain the file
fileinode — the inode to obtain the file
filemtime — Get file modification time
fileowner — Get the owner of the file
fileperms — Obtain permissions to files
filesize — Get file size
filetype — Get file type
flock — lightweight consultation file locking
fnmatch — match file names with pattern
fopen — Open a file or URL
fpassthru — all remaining data at the output file pointer
fputcsv — Format the line as CSV and write to the file pointer
fputs — an alias for fwrite()
fread — read files (safely used in binary files)
fscanf — Format input from a file
fseek — locate in file pointer
fstat — Get file information through the opened file pointer
ftell — Returns the location where the file pointer is read/write
ftruncate — truncate the file to a given length
fwrite — write to a file (safely used in binary files)
glob — Find file paths that match patterns
is_dir — This PHP file function determines whether the given file name is a directory
is_executable — determines whether the given file name is executable
is_file — determines whether the given file name is a normal file
is_link — determines whether the given file name is a symbolic connection
is_readable — determines whether the given file name is readable
is_uploaded_file — determines whether the file is uploaded through HTTP POST
is_writable — determines whether the given file name is writable
is_writeable — is_writable() alias
link — Create a hard connection
linkinfo — Get information about a connection
lstat — Gives information about a file or symbol connection
mkdir — Create a new directory
move_uploaded_file — Move uploaded files to a new location
parse_ini_file — parse a configuration file
pathinfo — Returns the information about the file path
pclose — Close process file pointer
popen — Open process file pointer
readfile — output a file
readlink — Returns the target pointed to by the symbolic connection
realpath — Returns the normalized absolute path name
rename — rename a file or directory
rewind — rewind the location of the file pointer
rmdir — delete directory
set_file_buffer — an alias for stream_set_write_buffer()
stat — gives information about the file
symlink — Create symbolic connection
tempnam — Create a file with a unique file name
tmpfile — Create a temporary file
touch — Set the file access and modification time
umask — Change the current umask
unlink — delete file
The above is all the content of this article. I hope it will be helpful to everyone's study and I hope everyone will support me more.