Chapter Summary

In this chapter, we studied the second of two key concepts related to functions: arguments (how objects are passed into a function). As we learned, arguments are passed into a function by assignment, which means by object reference, which really means by pointer. We also studied some more advanced extensions, including default and keyword arguments, tools for using arbitrarily many arguments, and keyword-only arguments in 3.0. Finally, we saw how mutable arguments can exhibit the same behavior as other shared references to objects—unless the object is explicitly copied when it’s sent in, changing a passed-in mutable in a function can impact the caller.