Monday, 1 August 2011

PHP - File Write

PHP - File Write

Now that you know how to open and close a file, lets get on to the most useful part of file manipulation, writing! There is really only one main function that is used to write and it's logically called fwrite.

PHP - File Open: Write

Before we can write information to our test file we have to use the function fopen
to open the file for writing.


PHP Code:

$myFile = "testFile.txt";
$fh = fopen($myFile, 'w');


PHP - File Write: fwrite Function

We can use php to write to a text file. The fwrite function allows
data to be written to any type of file. Fwrite's first
parameter is the file handle and its second parameter is the string of data that is to
be written. Just give the function those two bits of information and you're good to go!

Below we are writing a couple of names into our test file testFile.txt and separating
them with a carriaged return.


PHP Code:

$myFile = "testFile.txt";
$fh = fopen($myFile, 'w') or die("can't open file");
$stringData = "Bobby Bopper\n";
fwrite($fh, $stringData);
$stringData = "Tracy Tanner\n";
fwrite($fh, $stringData);
fclose($fh);


The $fh variable contains the file handle for testFile.txt.
The file handle knows the current file pointer, which for writing, starts out at the beginning of the file.
We wrote to the file testFile.txt twice. Each time we wrote to the file
we sent the string $stringData that first contained Bobby Bopper and second contained

Tracy Tanner. After we finished writing we closed the file using the fclose function.


If you were to open the testFile.txt file in NOTEPAD it would look like this:

Contents of the testFile.txt File:

Bobby Bopper


Tracy Tanner

PHP - File Write: Overwriting

Now that testFile.txt contains some data we can demonstrate what happens
when you open an existing file for writing. All the data contained in the file
is wiped clean and you start with an empty file. In this example we open our existing
file testFile.txt and write some new data into it.


PHP Code:

$myFile = "testFile.txt";
$fh = fopen($myFile, 'w') or die("can't open file");
$stringData = "Floppy Jalopy\n";
fwrite($fh, $stringData);
$stringData = "Pointy Pinto\n";
fwrite($fh, $stringData);
fclose($fh);

If you now open the testFile.txt file you will see that Bobby and Tracy
have both vanished, as we expected, and only the data we just wrote is present.


Contents of the testFile.txt File:

Floppy Jalopy

Pointy Pinto

In the next lesson we will show you how to get information out of a file by using PHP's
read data functions!

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