Enumerating Enumerable: Enumerable#drop

by Joey deVilla on July 10, 2008

Enumerating Enumerable marches on!

This is the seventh article in my series in which I try to do a better job of documenting Ruby’s Enumerable module than Ruby-Doc.org does. If you’ve missed the other articles in the series, they’re listed below:

  1. all?
  2. any?
  3. collect / map
  4. count
  5. cycle
  6. detect / find

In this installment, I cover a method added in Ruby 1.9: drop.

Enumerable#drop Quick Summary

Graphic representation of the \"drop\" method in Ruby\'s \"Enumerable\" module

In the simplest possible terms Given a collection and a number n, create an array made of the items of the collection with the first n items removed.
Ruby version 1.9 only
Expects The number of elements to remove from the start of the collection.
Returns An array made up of the remaining items, if there are any./td>
RubyDoc.org’s entry Enumerable#drop

Enumerable#drop and Arrays

With an array, drop takes a number n as an argument and returns an array created by removing the first n elements of the array. The resulting array is made up of the remaining elements.

Enumerable#drop and Hashes

With an hash, drop takes a number n as an argument and returns an array created by removing the first n elements of the array (drop is only in Ruby 1.9 and later, where hashes keep the order in which they were defined, so its results are predictable). The resulting array is made up of the remaining elements, with each element converted into a two-element array where element 0 is the key and element 1 is the corresponding value.

Enumerable#take: Enumerable#drop’s Evil Twin

I’ll cover take in detail in a later installment, but for now, an example should suffice:

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