File Read and Write

PHP offers quite a range of methods to read and write files. In the case below, I have chosen just to create and then read a simple three (3) field data base stored as a tab delimited text file. See http://au2.php.net/manual/en/ref.filesystem.php for much more detail and options.

Read a tab delimited text file

Write a program that will read three fields from a text file in tab delimited format and display the content on the screen.

The content of the file is <string field><tab><string field><tab><integer field><new line>

<?php

//File tab delimited file read in PHP and designed for use at the command line

fwrite(STDOUT, "\n Given \t Surname \t Age \n");

fwrite(STDOUT, "---------------------------------------------------------- \n");

if ( $fp = fopen('friends.txt','r') ) {

   while ($friendinfo = fscanf($fp, "%s\t%s\t%d\n")) {

       list ($given, $surname, $age) = $friendinfo;

       fwrite(STDOUT, $given." \t".$surname." \t".$age."\n");

   }

   fclose($fp);

}

else

{

 fwrite(STDOUT, "file not found \n");

}

exit(0);

?>

Note:

fopen creates a hadle to the file.

fopen returns false if the file does not exist so an if staement can be used to test if the file exists.

fscanf returns a false when the end of file is reached so the while lop can be terminated.

Write a tab delimited text file

Write a program that will accept values from the user and write them to a tab delimited text file.

The content of the file is <string field><tab><string field><tab><integer field><new line> 

<?php

//File tab delimited file write (append) in PHP and designed for use at the command line

if ( $fp = fopen('friends.txt','at') ) {

   fwrite(STDOUT, "how many friends do you want to enter --> ");

   fscanf(STDIN, "%d\n", $friends);

   for ($i=0; $i < $friends; $i++) {

       fwrite(STDOUT, "enter given name--> ");

       fscanf(STDIN, "%s\n", $given);

       fwrite(STDOUT, "enter surname--> ");

       fscanf(STDIN, "%s\n", $surname);

       fwrite(STDOUT, "enter age--> ");

       fscanf(STDIN, "%d\n", $age);

    //write date to file

    fwrite($fp, $given." \t".$surname." \t".$age."\n");

   }

   fclose($fp);

}

else

{

 fwrite(STDOUT, "file not found \n");

}

exit(0);

?>

Note:

The "a" parameter in the fopen function allows you to append to a file. The "t" parameter is for Windows files only and is to endure that  a CR LF sequence is put at the end of the record.

Exercises

1. Create a simple database management system by combining the two programs above into procedures. Then use an array to store your data while in memory. Create a simple sort function that will sort your data into age order.
2. ex2
3. ex3