Codes Tips

Description

I want to begin the first post about PHP with something easy, but very useful. Writing and reading to/from files in PHP.
Here is a short description for reading from file in PHP:

1. Open the file for reading
2. If the open was successful then we can read from the output file
3. After we read from file we should close the file.

Here is a short description for writing to files in PHP:

• Open the file for writing
• If the open was successful then we can Write to the output file
• After we wrote to file we should close the file.

OPENING

To open a file in PHP you should use the function fopen:

pointer fopen( string $filepath, string $mode)

This function return a pointer resource when the $filepath exists or FALSE when the file doesn’t exist.

$filepath is the path to the file that we want to open.
$mode - this is the type of access when reading or writing to files

• r - opens the file for reading only
• r+ - open the file for reading/writing and places the file at the begining of the file
• w - opens the file for writing only
• w+ - opens the file for reading/writing places the pointer at the beginning of the file and truncate the size of the file to 0
• a - places the pointer at the end of the file for writing(append)
• a+ - places the pointer at the end of the file for reading and writing(append).
• x - opens for writing, places pointer at the begining of the file.
• x+ - opens for writing/reading, places pointer at the begining of the file.

READING

You can use more functions for reading from file after you open it:
fread($filepointer,$nbytes)
$filepointer - a pointer to the file
$nbytes - number of bytes you wanna read from file. (a character have a size of a byte)

fgets($filepointer) - reads a line from the file
fgetc($filepointer) - reads a caracter from file

WRITING

You can used fwrite($filepointer, $datastring) to write a string to file

CLOSING

After you finished writing/reading from file you shuld use:
fclose($filepointer) - to close the file

Example of codes:

For reading the first 10 caracters from a file you can use the folowing block of code:

$f=fopen("c:\\path\\file.txt","r");
$string = fread($f,10);
fclose($f);

Reading an entire file to a string variable character by character:

$f=fopen("c:\\file.txt","r");
$textstring="";
while (!feof($f))
{
$c=fgetc($f);
$textstring=$textstring.$c;
}
fclose($f);

Reading a file quickly:

$path = "c:\\file.txt";
$f=fopen($path,"r");
$textstring = fread($f,filesize($path));
fclose($f);

Writing a two lines of string to a file

$path = "myfile.txt";
$f = fopen($path, 'w') or die("error opening the file");
$allstring="this is the first line of the test\nthis is the second line of the test";
fwrite($f,$allstring);
fclose($f);

Additional functions that you can be useful for file handling are:

feof($filepointer) - test if the end of file was reached.
file_exists($filepointer) - tests if a a file exists
die() or exit() - terminate the script that is currently executed.

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