A few Ruby tips to share

This article mainly introduces a few Ruby tips to share, this article explains the code block sequence calls, mainly said that the array in blocks in the use, Hash#fetch, create code snippets and other tips, the need for friends can refer to the

Sequence calls to code blocks

The code is as follows:

def Touch_down

Yield [3, 7]

Puts "touchdown!"

End

Touch_down do | (First_down, Second_down) |

Puts "#{first_down} yards on the run"

Puts "#{second_down} yards passed"

End

=> "3 yards on the run"

=> "7 yards passed"

=> "touchdown!"

The main is that the use of array in block

To remove an element from an array

The code is as follows:

>> args = [1, 2, 3]

>> a rest = args

>> A

=> 1

>> Rest

=> [2, 3]

It was just clear how the split sequence was used, and we didn't notice that we could easily get the rest of the sequence.

Hash#fetch

The code is as follows:

>> items = {: Apples => 2,: Oranges => 3}

=> items = {: Apples=>2,: Oranges=>3}

>> Items.fetch (: Apples)

=> 2

>> Items.fetch (: bananas) {|key| "We don ' t carry #{key}!"}

=> We don ' t carry bananas!

When hashing is used, fetch may be more convenient than checking for the existence of a value.

To create a hash of a code snippet

The code is as follows:

>> smash = hash.new {|hash, key| hash[key] = "A #{key} just got smashed!"}

=> {}

>> smash[:p Lum] = "Cannot smash."

=> {:p lum=> "cannot smash."}

>> Smash[:watermelon]

=> {:p lum=> "cannot smash.",:watermelon=> "a watermelon just got smashed!"}

Using a snippet to produce a hash makes it easy to maintain some undefined initial values, especially in the Fibonacci calculations (I didn't see how to use them).

Array#sort_by

The code is as follows:

>> cars =%w[beetle Volt Camry]

=> ["Beetle", "Volt", "Camry"]

>> cars.sort_by {|car| car.size}

=> ["Volt", "Camry", "Beetle"]

The Sort_by method of the sequence is used to sort the return value of the code snippet, just as for the Symbol#to_proc map or sort

String#present?

The code is as follows:

>> "Brain". Present?

=> true

>> "". Present?

=> false

Rails developers may be familiar with blank, but what about present? It's also a good way to actually determine if the return value is correct.

Here I do think about the difference between find (: All) and see (: a) whether there is a return value. There is also a

. exists?

. Empty?

. Blank?

. Nil?

See more.