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Some drops of PHP

Parsing a string

Parse string: sscanf()

With sscanf() function you can parse a string following a well known pattern.

For example, think about the ISBN code. The ISBN code is the code identifier for books, it is 13 chars long and it is defined as:

  • first 3 digits are the Ean code;
  • then a separator with -;
  • 1 digit for group;
  • then a separator with -;
  • 3 digits for publisher;
  • then a separator with -;
  • 5 digits for the title;
  • then a separator with -;
  • 1 digit for check.

An example is : “978-0-596-52068-7”

If you want to parse the ISBN code and extract the parts you can use the sscanf() function. The sscanf() function has at least 2 parameters:

  • the first parameter is the string to parse (“978-0-596-52068-7”)
  • the second parameter is the pattern, composed with some placeholders. For example with %d you can decalre a digit. In the case of isbn you can specify: "%d-%d-%d-%d-%d" that it means : a number followed by the - char, another number followed by the - char, another number followed by the - char, another number followed by the - char, another number followed by the - char.
$isbn = "978-0-596-52068-7";
list($ean, $group, $publisher, $title, $check_digit) =
    sscanf($isbn, "%d-%d-%d-%d-%d");
echo "EAN: " . $ean . PHP_EOL;
echo "Group: " . $group . PHP_EOL;
echo "Publisher: " . $publisher . PHP_EOL;
echo "Title: " . $title . PHP_EOL;
echo "Check digit: " . $check_digit . PHP_EOL;