Detailed explanation of PHP file operations_PHP tutorial

This article is a detailed tutorial on PHP file operations. It is very detailed and comprehensive. I share it with you now. I hope it will be helpful to friends who are learning PHP development.

The code is as follows:
$path1= "E:/myphp/text.txt";
if(!file_exists($path1)){
echo "File does not exist!";
}else{
$handle1 = fopen($path1, 'r+') or exit("Unable to open file");
// while (!feof($handle1)){
// echo fgets($handle1)."
";
// }
while(!feof($handle1)){
echo fgetc($handle1);
}
}

The above code illustrates a simple file reading operation. Description:
fopen is to open file resources.
How to use:
$file=fopen("welcome.txt","r");
Specific meaning: The first parameter is the path of the file. The following parameter is the method required to open the file, which has the following types:
r Read only. Start at the beginning of the file.
r+ read/write. Start at the beginning of the file.
w write only. Opens and clears the contents of the file; if the file does not exist, creates a new file.
w+ read/write. Opens and clears the contents of the file; if the file does not exist, creates a new file.
a append. Opens and writes to the end of a file, or creates a new file if it does not exist.
a+ read/append. Maintain file contents by writing to the end of the file.
x Write only. Create new file. Returns FALSE if the file already exists.
x+
read/write. Create new file. If the file already exists, returns FALSE and an error.

Note: If fopen() cannot open the specified file, it returns 0 (false).
The more commonly used ones are the first 4.
fgetc:
string fgetc ( resource$handle )
Returns a string containing one character obtained from the file pointed to by handle. Returns FALSE if EOF is encountered.

fgets:
string fgets ( int$handle [,int$length ] )
Reads a line from the file pointed to by handle and returns a string of length at most length - 1 bytes. 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.
Returns FALSE on error.

fgetss:
string fgetss ( resource$handle [,int$length [,string$allowable_tags ]] )
Same as fgets(), except fgetss attempts to strip any HTML and PHP tags from the text being read. (Same as fgets(), except that it filters html and php tags.)
The optional third parameter can be used to specify which tags are not to be removed.
The feof() function detects whether the end of file (eof) has been reached.

//Determine whether the file or directory exists
bool file_exists(string filename)
Determine whether the file or directory exists, return true if it exists, otherwise return false
Format:

The code is as follows:
if(file_exists(“hello.txt”))
{
Echo "File exists";
}
//Open file

Format:
fopen(filename,mode)
Description: Open the specified file in the specified format
filename: the file name to be opened
mode: open mode
fopen("hello.txt","w");
Indicates opening the hello.txt file in writing

//Write file
Format:
fwrite(resource,string);
Description: Add the specified content to the opened file
resource:open file
string: Content to be written
Example:
$handle = fopen(“hello.txt”,”w”) //If a, data can be appended
fwrite($handle,”1rn”)

//Close the file
Format:
fclose($handle)
Description: Close the open file
Example:
$handle = fopen("hello.txt","w");
fclose($handle);

//Read a row of data
Format:
fgets(int handle[,int length])
Description: Read length-1 characters. If length is not specified, the default byte size is 1KB,
If a newline, EOF is encountered or length-1 characters have been read, the program terminates,
Return false when an error occurs;
Example:
$handle = fopen(“hello.txt”,”r”);
$buffer = fgets($handle,1024);
echo $handle; //Output a line of information

//Read the entire file
Format:
readfile(filename)
Description: Read the entire file and output it to the browser
Example:
readfile(“hello.txt”);
?>

//Get file size
Format:
filesize(filename)
Description: Get the specified file size, return false
if an error occurs Example:
filesize(“a.rar”)

//Delete files
Format:
unlink()
Description: Delete a file, return true if successful, otherwise return false
Example:
unlink(“b.txt”)

//Create directory
Format:
mkdir(dirname)
Description: Create a directory
Example: mkdir(“newfolder”); //Create a new folder in the current directory

//Delete directory
Format:
rmdir(dirname)
Description: Delete a directory
Example: rmdir(“newfolder”);

//Get the file name
Format:
basename(filepath)
Description: Return the file name
from the specified path Example:
basename("c:mytoolsa.txt") //return a.txt

//Get file path information
pathinfo(path)
Description: Return file path information, the result is saved in an array, the array subscript is
dirname (path), basename (file name), extension (extension)
Example: pathinfo(“c:mytoolsa.txt”)

//Get absolute path
Format:
realpath(filename)
Description: Get the absolute path of the specified file, and return false
if it fails. Example: realpath(“h.txt”) //F:apachewww.jnwebseo.comh.txt

//Copy file
Format:
copy(source,dest)
Instructions: Copy the source file to dest
Example: copy(“h.txt”,”newflodera.txt”)

//Determine whether it is a directory
Format:
is_dir(filename)
Description: Determine whether the given file name is a directory. If filename exists and
If it is a directory, it returns true, otherwise it returns false.
Example:

The code is as follows:
if(is_dir(“newfolder”))
{
echo "is a file directory";
}

//Open directory
Format: opendir(path)
Description: Open a specified file directory and return a resource identifier
Example:
$hand = opendir(“.”) //Open the root directory

//Read directory
Format:
readdir($handle)
Description: Read an open file directory stream
readdir($hand);

//Close directory
Format:
closedir($handle)
Description: Close an open directory stream
Example: closedir($hand);