ruby hash方法

Hash.rassoc(obj)方法 (Hash.rassoc(obj) Method)

In this article, we will study about Hash.rassoc(obj) Method. The working of the method can’t be assumed because of it’s quite a different name. Let us read its definition and understand its implementation with the help of syntax and program codes.

在本文中，我們將研究Hash.rassoc(obj)方法 。 由于該方法的名稱完全不同，因此無法進行假設。 讓我們閱讀其定義并在語法和程序代碼的幫助下了解其實現。

Method description:

方法說明：

This method is a Public instance method and belongs to the Hash class which lives inside the library of Ruby language. The Hash.rassoc() method is used to check whether a value(key-value) is a part of the particular Hash instance or not and that Hash instance should be the normal Hash instance. An abnormal means that Hash instance is the Hash of multiple Array instances along with with their keys or you can say that it the collection of multiple keys and values which are itself an object of Array class. Let us go through the syntax and demonstrating the program codes of this method.

此方法是Public實例方法，屬于Hash類，它位于Ruby語言庫中。 Hash.rassoc()方法用于檢查值(鍵值)是否為特定Hash實例的一部分，并且該Hash實例應為普通Hash實例。 異常意味著Hash實例是多個Array實例及其鍵的哈希，或者可以說它是多個鍵和值的集合，而這些鍵和值本身就是Array類的對象。 讓我們來看一下語法，并演示該方法的程序代碼。

If you are thinking about what it will return then let me tell you, it will return the first contained Hash instance where it found the presence of the value in Key-value pair. It will return "nil" if it hadn't found the value in any of the Hashes.

如果您正在考慮它將返回什么，那么讓我告訴您，它將返回第一個包含的Hash實例，在該實例中發現鍵值對中存在該值。 如果在任何哈希中都找不到該值，它將返回“ nil” 。

Syntax:

句法：

    Hash_instance.rassoc(obj)

Argument(s) required:

所需參數：

This method only takes one parameter and that argument is nothing but an object whose presence we want to check.

此方法僅使用一個參數，而該參數不過是一個要檢查其存在性的對象。

Example 1:

范例1：

=begin
Ruby program to demonstrate Hash.rassoc method
=end	
hsh = {"colors"  => "red",
"letters" => "a", "Fruit" => "Grapes"}
puts "Hash.rassoc implementation:"
puts "Enter the Value you want to search:-"
ky = gets.chomp
if (hsh.rassoc(ky))
puts "Value found successfully"
puts "Values are: #{hsh.rassoc(ky)}"
else
puts "Value not found!"
end

Output

輸出量

Hash.rassoc implementation:
Enter the Value you want to search:-
blue
Value not found!

Explanation:

說明：

In the above code, you can find that the Hash instance on which we have invoked the Hash.rassoc() method is a normal Hash instance. It is not the collection of multiple Array instances along with their specific keys. It is returning the whole Array instance with the key where it has found the value inputted by the user.

在上面的代碼中，您可以發現我們在其上調用Hash.rassoc()方法的Hash實例是普通的Hash實例。 它不是多個Array實例及其特定鍵的集合。 它返回整個Array實例，并返回找到用戶輸入值的鍵。

Example 2:

范例2：

=begin
Ruby program to demonstrate Hash.rassoc method
=end	
hsh = {"color"=> ["green","blue","yellow"],"vege"=> ["papaya","brinjal"]}
puts "Hash rassoc implementation:"
puts hsh.rassoc("green")

Output

輸出量

Hash rassoc implementation:

Explanation:

說明：

In the above code, you can verify that the Hash.rassoc() method does not work upon abnormal Hash instances. It will return nil even if the value is present in the Hash.

在上面的代碼中，您可以驗證Hash.rassoc()方法不適用于異常的Hash實例。 即使哈希中存在該值，它也將返回nil。

翻譯自: https://www.includehelp.com/ruby/hash-rassoc-obj-method-with-example.aspx

ruby hash方法