Section 22 Function: Arguments

22.1 Formal argument

• Arguments that must be supplied with appropriate values while calling the function.

22.2 Default argument value

• Arguments with default value will be considered if no value is given while calling the function.

22.3 Argument matching

• Matched by argument names

• Matched by argument positions

• Matched by a mix of argument names and positions

• Partial matching is possible

• Order of argument matching

  • Check for the exact match
  • Check for the partial match
  • Check for the positional match

22.4 The ... argument

• A way to provide further arguments to or from other functions

?cat
?rep
?seq
?paste
?mean

• Advantage of ... arguments
  • to extend the functionality of another function
  • when the number of arguments passed to the function cannot be known in advance
  • arguments comming after the ... must be named explicitly and cannot be partially matched or matched positionally