In this chapter, you were introduced to basic looping in Ruby. This chapter discussed the while loop, which is a low level iteration mechanism, the each loop, which is one of the more common looping tools in programs, and the for...in loops in Ruby. We saw how to iterate a key/value hash.
We examined how to utilize the enumerable select method and learned three different ways to use the select method.
You learned about the map method and how it can be utilized to change each element of a collection. We also walked through three different ways to use the map method and some of the more advanced components that map provides.
Lastly, this chapter walked us through how you can leverage the inject method to perform calculations on each element in an array while keeping track of the accumulated value.
In the next chapter, we'll examine the array data structure.
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