create PHP array using fopen with append

I am having trouble figuring out how to write to a file using fopen "a" append mode.

the file itself is a simple PHP array:

$array = array(
  "entry1"   => "blah blah",
  "entry2"   => "forbarbaz",
);   

simple enough. So using fopen with the 2nd arg set to "a" should allow me to append the file using fputs.... the problem is the opening and closing lines, ie $array = array( and );

so now the file should look like this:

  "entry1"   => "blah blah",
  "entry2"   => "forbarbaz",

how would I rebuild this data into a working PHP array assuming it is just a txt file with a list of entries without the opening and closing lines? Sorry if this is not clear, its a little complicated. No I am not going to store these values in a DB, I need the speed advantage by holding these particular values in a file array.

So the questions really is how would i go about constructing the usable PHP array from a txt file with a line by line list like this?

To clarify:

how do i pull in a txt file with lines like this:

  "entry1"   => "blah blah",
  "entry2"   => "forbarbaz",

and have a workable $php_array()????

Try this.

File format (at the beginning of work with it):

<?php
$array = array();

Now it's correct php-file.

Then simply add new rows like as follows:

$f = fopen('myarray.php', 'a');
fputs($f, PHP_EOL.'$array["entry1"] = "value1";');
fclose($f);

And use it by simply include('myarray.php');