Hello drose2211,

The sprintf function applies the formatting specified in the template supplied as its first argument, to produce a string using the remaining arguments. In this case, the template ' %d/%d ' means: print a space, followed by the next argument formatted as an integer, followed by a slash, followed by the next argument formatted as an integer, followed by a space. Without the sprintf function, the code would be longer and less elegant:

$line =~ s{ \s (M?\d{2}) / (M?\d{2}) \s }
          { ' ' . int(convert($1)) . '/' . int(convert($2)) . ' ' }xeg
+;
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(Perl’s printf and sprintf functions are derived from their equivalents in C. In Perl, there is also print, which does not take a template, but there is no corresponding sprint.)

Hope that helps,

drose2211:   Further to Athanasius's post:   Note also that the  s/// substitution operator needs the  /e modifier to be able to evaluate an arbitrary expression in its replacement block. See  s/PATTERN/REPLACEMENT/ in Regexp Quote-Like Operators in perlop.