Core Function Scanf

Revision as of 17:32, 22 January 2013

Scanf( <expression>, <def> )

Description

Parses input from a string according to a format.

Parameters

expression

The string to evaluate.

def

The formation string containing the definition of how to parse the string.

extra ...

Optionally pass in variables by reference that will contain the parsed values.

Return Value

Success: Returns array of all captured objects from the parsed string.

Failure: Returns empty array.

Remarks

If only two parameters were passed to this function, the values parsed will be returned as an array. Otherwise, if optional parameters are passed, the function will return the number of assigned values.

If there are more substrings expected in the format than there are available within str, they will be ignored and you will get what did match.

Example

my $RET = Scanf("X123 Y456", "X%d Y%d");
printr($RET);
 
my $RET = Scanf("Copyright 2009-2011 CompanyName (Multi-Word Message)", "Copyright %d-%d %s (%[^)]");
printr($RET);

Example #1 sscanf() Example

// getting the serial number
list($serial) = Scanf("SN/2350001", "SN/%d");
// and the date of manufacturing
$mandate = "January 01 2000";
list($month, $day, $year) = Scanf($mandate, "%s %d %d");
println("Item $serial was manufactured on: $year-" . substr($month, 0, 3) . "-$day");

Example #2 sscanf() - using optional parameters If optional parameters are passed, the function will return the number of assigned values.

// get author info and generate DocBook entry
$auth = "24\tLewis Carroll";
$n = Scanf($auth, "%d\t%s %s", $id, $first, $last);
print("<author id='$id'>
    <firstname>$first</firstname>
    <surname>$last</surname>
</author>\n");

Example of how to parse a file name without getting the . trapped inside the first %s

$out = scanf('file_name.gif', 'file_%[^.].%s', $fpart1, $fpart2);
println("Name '$fpart1' Ext '$fpart2'");

Example of using [] to spawn a character set

$date = 'january-2008';
// notice it is scanning for all characters a-z and uppercase A-Z
// so it will match any case of the month name
Scanf($date, '%[a-zA-Z]-%d', $month, $year);
println("Parsed values: '$month', '$year'");