Detailed explanation of file operations based on PHP_PHP tutorial

Introduction to knowledge points:
1. Determine whether the file or directory exists bool

Copy the code The code is as follows :

file_exists(string filename)

2. Get the file name

Copy code Code As follows:

basename(filepath)

3. Open the file

Copy the code The code is as follows :

fopen(filename,mode)

4. Get file path information

Copy code The code is as follows:

pathinfo(path)

5. Write file

Copy code The code is as follows:

fwrite(resource,string)

6. Take the absolute path

Copy code The code is as follows:

realpath(filename)

7. Close the file

Copy the code The code is as follows:

fclose($handle)

8. Copy the file

Copy the code The code is as follows:

copy(source,dest)

9. Read a row of data

Copy code The code is as follows:

fgets(int handle[,int length])

10. Determine whether it is a directory

Copy code The code is as follows:

is_dir(filename)

11. Read the entire file

Copy code The code is as follows:

readfile(filename)

12. Open the directory

Copy code The code is as follows:

opendir(path)

13. Get the file size

Copy code The code is as follows:

filesize(filename)

14. Read directory

Copy code The code is as follows:

readdir($handle)

15. Delete files

Copy code The code is as follows:

unlink()

16. Close the directory

Copy code The code is as follows:

closedir($handle)

17. Create directory

Copy the code The code is as follows:

mkdir(dirname)

18. Delete the directory

Copy the code The code is as follows:

unlink() 

19. Determine whether the file or directory exists

Copy code The code is as follows:

bool file_exists(string filename)

20. Determine whether the file or directory exists, and return true if it exists , otherwise return false
Format:

Copy code 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 name of the file to be opened
mode: Open mode
fopen("hello.txt", "w");
means opening the hello.txt file in writing mode

Writing file

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

Close the file

Format:
fclose($handle)
Description: Close the open file
Example:

Copy code The code is as follows:

$handle = fopen("hello.txt","w");
fclose($handle);

Read a line of data

Format:
fgets(int handle[,int length])
Description: Read length-1 characters. If length is not specified, the default byte is 1KB.
If a newline, EOF or length-1 characters have been read, the program will terminate.
Return false when an error occurs;
Example:

Copy code The code is as follows:

$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:

Copy code The code is as follows:

readfile(“hello.txt”);
?>

Get file size

format :
filesize(filename)
Description: Get the specified file size, return false on error
Example:
filesize("a.rar")

Delete file

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 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")

Take the absolute path

Format:
realpath(filename)
Description : Take the absolute path of the specified file, return false
if it fails. Example: realpath("h.txt") //F:apacheexampleh.txt

Copy file

Format:
copy(source,dest)
Description: 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
is a directory, return true, otherwise return false.
Example:

Copy code The code is as follows:

if(is_dir(“newfolder”))
{
echo “is the 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) ;

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