Your task is to implement the following public methods of the NestedArray class. Consult the description of Enumerable module for methods' behavior. The starting point of the code is here.
to_s method to return the contents of the nested
array as a string. Make sure that all the nested elements appear in
the string and the
structure of the nesting is displayed.find method that returns any one element (in
any of the nested arrays) for
which the given block is not false. For instance, if I consider the
nested array NestedArray.new([[6,7],[8],[[9, 6]]]).find {|y| y >
7} then the method may return 8. Note that returning 9 would
be correct as well. If the block is false on all elements, nil is
returned.any? method that returns true if the block
returns a value other than false or nil on at least one element,
otherwise it returns falsemap method that returns a new nested array of
the same structure with the results of running block once for every
element. For instance,
NestedArray.new([[6,7],[8],[[9, 6]]]).map {|y| y * y}
[[36,49],[64],[[81, 36]]].
inject method that takes a "seed"
and works on all elements according to the definition in the
Enumerable module. For instance,
NestedArray.new([[6,7],[8],[[9, 6]]]).inject(1) {|prod, y| prod * y}
Don't worry about default parameters or type mismatches for any of the methods: they need to work on the correct input and are allowed to break on any incorrect data.
You may define any private methods that you find helpful. If you run into any problems with making methods private, you can make your helper methods public without loss of credit, just use _ in front of the name to distinguish "private" methods from public ones.
There are two ways to approach this problem: use the each
method above as a sample and just write all the other methods one by
one, or write a more general traverse-like method and use it to
generate all of the needed methods. The latter approach requires using
a lambda rather than a block since we need to pass two functions to
traverse (action and combine), but we can
pass only one block.
You may use either approach. No extra credit is given for the lambda
approach because once you get traverse to work, the rest of the
methods can be written in 20 minutes, if not less, so you are
simplifying the work quite a bit.