php - Overwriting Text in a File When It's Already Open -

i have file i'm opening writing, this:

if (!$idhandle = fopen($filename, 'w')) {         echo "cannot open file ($filename)";         die();     } 

i enter loop i'm incrementing variable, $beerid, during each iteration. want save variable file have open, use following code:

if (fwrite($idhandle, $beerid) === false) {     echo "cannot write file ($filename)";     die();     } $beerid++; 

however, ends creating massive string of every beerid encounter. want have file populated last id left off on.

i realize put write outside of loop, script volatile , terminate prematurely error, want have reference last $beerid variable in event of error terminates script before loop terminated.

you must go beginning of file because fwrite keeps track of in file. use fseek. opening , closing file several times in loop expensive , don't see reason in case. should of course close file when you're done it.

you should add before write file:

fseek($idhandle, 0); 

that move beginning of file, since incrementing values won't have worry removing previous value.

edit in answer above assume id's encountered incremented values, don't so, if example encounter id=10, , encounter id=1 above still result in 10 in file, handle add padding string you're writing using str_pad:

str_pad($value_to_write, 10); //or whatever value reasonable.