Improve English method examples for Ruby's guide (#29087)
* Improve English method examples for Ruby's guide * Improve ruby common array methods examples * Minor fix in array examplespull/30728/head^2
Ignacio Capuccio
The Coding Aviator
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@ -9,18 +9,25 @@ For the purpose of this guide, our array will be as follows:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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```
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#### .length
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The .length method tallies the number of elements in the array and returns the count:
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The `.length` method tallies the number of elements in the array and returns the count:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.length
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=> 5
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```
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This is also similar to .count and .size methods.
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This is also similar to `.count` and `.size` methods.
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.count
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=> 5
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@ -29,41 +36,62 @@ array.size
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```
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#### .first
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The .first method returns the first element of the array, the element at index 0:
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The `.first` method returns the first element of the array, the element at index 0:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.first
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=> 0
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```
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#### .last
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The .last method returns the last element of the array:
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The `.last` method returns the last element of the array:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.last
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=> 4
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```
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#### .take
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The .take method returns the first n elements of the array:
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The `.take` method returns the first n elements of the array:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.take(3)
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=> [0, 1, 2]
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array
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=> [0, 1, 2, 3, 4]
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```
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#### .drop
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The .drop method returns the elements after n elements of the array:
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The `.drop` method returns the elements after n elements of the array:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.drop(3)
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=> [3, 4]
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array
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=> [0, 1, 2, 3, 4]
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```
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#### array index
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You can return a specific element in an array by accessing its index. If the index does not exist in the array, `nil` will be returned:
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```ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array[2]
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=> 2
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@ -72,155 +100,250 @@ array[5]
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```
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#### .pop
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The .pop method will permanently remove the last element of an array and return this element:
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The `.pop` method will permanently remove the last element of an array and return this element:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.pop
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=> 4
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array
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=> [0, 1, 2, 3]
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```
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#### .shift
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The .shift method will permanently remove the first element of an array and return this element:
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The `.shift` method will permanently remove the first element of an array and return this element:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.shift
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=> 0
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=> 0
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array
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=> [1, 2, 3, 4]
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```
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#### .push
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The .push method will add an element to the end of an array:
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The `.push` method will add an element to the end of an array and return the array:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.push(99)
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=> [0, 1, 2, 3, 4, 99]
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array
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=> [0, 1, 2, 3, 4, 99]
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```
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#### .unshift
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The .unshift method adds an element to the beginning of an array:
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The `.unshift` method adds an element to the beginning of an array and return the array:
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```
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array = [2, 3]
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array.unshift(1)
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=> [1, 2, 3]
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.unshift(99)
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=> [99, 0, 1, 2, 3, 4]
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array
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=> [99, 0, 1, 2, 3, 4]
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```
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#### .delete
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The .delete method removes a specified element from an array permanently:
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``` ruby
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array.delete(1)
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=> [0, 2, 3, 4]
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```
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#### .delete_at
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The .delete_at method permanently removes an element of an array at a specified index:
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``` ruby
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array.delete_at(0)
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=> [1, 2, 3, 4]
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```
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#### .reverse
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The .reverse method reverses the array but does not mutate it (the original array stays as is):
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``` ruby
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array.reverse
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=> [4, 3, 2, 1, 0]
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```
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#### .select
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The .select method iterates over an array and returns a new array that includes any items that return true to the expression provided.
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``` ruby
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array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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array.select { |number| number > 4 }
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=> [5, 6, 7, 8, 9, 10]
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```
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#### .include?
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The include? method checks to see if the argument given is included in the array and returns `true` if it is:
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The `.delete` method removes a specified element from an array permanently and return the element:
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``` ruby
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array = [1, 2, 3, 4, 5]
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=> [1, 2, 3, 4, 5]
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array.delete(3)
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=> 3
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array
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=> [1, 2, 4, 5]
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```
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#### .delete_at
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The `.delete_at` method permanently removes an element of an array at a specified index and return the element:
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``` ruby
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array = [1, 2, 3, 4, 5]
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=> [1, 2, 3, 4, 5]
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array.delete_at(3)
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=> 3
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array
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=> [1, 2, 3, 5]
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```
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#### .reverse
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The `.reverse` method returns a new array that includes the elements of the original array but in reverse order:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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new_array = array.reverse
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=> [4, 3, 2, 1, 0]
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new_array
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=> [4, 3, 2, 1, 0]
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array
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=> [0, 1, 2, 3, 4]
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```
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#### .select
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The `.select` method iterates over an array and returns a new array that includes any items that return true to the expression provided:
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``` ruby
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array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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new_array = array.select { |number| number > 4 }
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=> [5, 6, 7, 8, 9, 10]
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new_array
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=> [5, 6, 7, 8, 9, 10]
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array
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=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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```
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#### .include?
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The `.include?` method checks to see if the argument given is included in the array and returns `true` if it is:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.include?(3)
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=> true
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array.include?(5)
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=> false
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```
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#### .flatten
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The flatten method can be used to take an array that contains nested arrays and create a one-dimensional array:
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The `.flatten` method can be used to take an array that contains nested arrays and create a one-dimensional array:
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``` ruby
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array = [1, 2, [3, 4, 5], [6, 7]]
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array.flatten
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=> [1, 2, [3, 4, 5], [6, 7]]
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new_array = array.flatten
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=> [1, 2, 3, 4, 5, 6, 7]
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new_array
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=> [1, 2, 3, 4, 5, 6, 7]
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array
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=> [1, 2, [3, 4, 5], [6, 7]]
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```
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#### .join
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The .join method returns a string of all the elements of the array separated by a separator parameter. If the separator parameter is nil, the method uses an empty string as a separator between strings.
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The `.join` method returns a string of all the elements of the array separated by a separator parameter. If the separator parameter is nil, the method uses an empty string as a separator between strings:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.join
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=> "1234"
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=> "01234"
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array.join("*")
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=> "1*2*3*4"
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=> "0*1*2*3*4"
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array
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=> [0, 1, 2, 3, 4]
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```
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#### .each
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The .each method iterates over each element of the array, allowing you to perform actions on them.
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The `.each` method iterates over each element of the array, allowing you to perform actions on them:
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``` ruby
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array.each do |element|
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puts element
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end
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.each { |element| puts element }
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=>
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0
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1
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2
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3
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4
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array
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=> [0, 1, 2, 3, 4]
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```
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#### .map
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The .map method is the same as the .collect method. The .map and .collect methods iterate over each element of the array, allowing you to perform actions on them. The .map and .collect methods differ from the .each method in that they return an array containing the transformed elements.
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The `.map` method is the same as the `.collect` method. The `.map` and `.collect` methods iterate over each element of the array, allowing you to perform actions on them. The `.map` and `.collect` methods differ from the `.each` method in that they return an array containing the transformed elements:
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``` ruby
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array.map { |element| element * 2 }
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puts element
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end
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=>
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0
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2
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4
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6
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8
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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new_array = array.map { |element| element * 2 }
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=> [0, 2, 4, 6, 8]
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new_array
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=> [0, 2, 4, 6, 8]
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array
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=> [0, 1, 2, 3, 4]
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```
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#### .uniq
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The .uniq method returns a copy of the array containing only unique elements--any duplicate elements are removed from the array. The original array is not modified.
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The `.uniq` method returns a copy of the array containing only unique elements. Any duplicate elements are removed from the array. The original array is not modified.
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``` ruby
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array = [1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 6, 7, 8]
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array.uniq
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=> [1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 6, 7, 8]
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new_array = array.uniq
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=> [1, 2, 3, 4, 5, 6, 7, 8]
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new_array
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=> [1, 2, 3, 4, 5, 6, 7, 8]
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array
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=> [1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 6, 7, 8]
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```
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#### .concat
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The .concat method appends the elements from an array to the original array. The .concat method can take in multiple arrays as an argument, which will in turn append multiple arrays to the original array.
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The `.concat` method appends the elements from an array to the original array. The `.concat` method can take in multiple arrays as an argument, which will in turn append multiple arrays to the original array:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.concat([5, 6, 7], [8, 9, 10])
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=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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array
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=> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
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```
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#### .clear
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The .clear method will delete all the data in the array:
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The `.clear` method will delete all the data in the array:
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``` ruby
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array = [0, 1, 2, 3, 4]
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=> [0, 1, 2, 3, 4]
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array.clear
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=> []
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array
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=> []
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```
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