ruby end if_Ruby Set方法| delete_if（）和keep_if（）

妖狐艹你老母 2023-03-05 13:28 5阅读 0赞

ruby end if

There are several methods present in the Ruby library specifically defined to fulfill the requirements of Set objects. **delete\_if() and keep\_if()** are two functions which have certain specified tasks. The purpose of both the methods is the opposite of each other but they have a similarity that the executions of both are dependent upon a certain Boolean condition. If the Boolean condition comes out to be true then only the method will be executed, otherwise, they would not be executed. Let us see what they both are being used for. The rest of the article will let you know about the implementation of both methods with the help of examples.

Ruby库中存在几种专门定义的方法，这些方法可以满足Set对象的要求。 **delete\_if()和keep\_if()**是具有某些指定任务的两个函数。 这两种方法的目的是相反的，但它们的相似之处在于两者的执行都取决于特定的布尔条件。 如果布尔条件成立，则仅将执行该方法，否则将不执行它们。 让我们看看它们都被用来做什么。 本文的其余部分将通过示例帮助您了解这两种方法的实现。

## delete\_if()方法 **(**delete\_if() method**)** ##

**delete\_if() method** is used to delete all the elements of the Set object or you can say that it can delete the whole set at once but it is dependent upon a condition. If that **'if' condition** comes out to be true which is sheltering **delete\_if() method**, then all the contents of the Set will be deleted otherwise no element will be deleted from the instance of Set class.

**delete\_if()方法**用于删除Set对象的所有元素，或者可以说它可以一次删除整个集合，但取决于条件。 如果**隐含delete\_if()方法的** **'if'条件**成立，则Set中的所有内容都将被删除，否则不会从Set类的实例中删除任何元素。

This method does not take any argument. It returns self moreover, it returns enumerator if you will not provide it a block. Let us see its example for having a better understanding of its concept.

此方法不带任何参数。 此外，它返回self，如果不为它提供块，则返回枚举器。 让我们看看它的示例，以更好地理解其概念。

**Example:**

**例：**

=begin
    Ruby program to implement delete_if?().
    =end
    require 'set'
    
    Vegetable=Set.new(["potato","brocolli","broccoflower","lentils","peas","fennel","chilli","cabbage"])
    
    puts "Enter the number of element you want in the Set:"
    num = gets.chomp.to_i
    
    if Vegetable.count > num
    	Vegetable.delete_if()
    	puts "Set overloaded. Set emptied"
    else
    	puts "Set is not overloaded"
    end

**Output**

**输出量**

RUN 1:
    Enter the number of element you want in the Set:
     12
    Set is not overloaded
    
    RUN 2:
    Enter the number of element you want in the Set:
     2
    Set overloaded. Set emptied

**Explanation:**

**说明：**

In the above code, you can observe that we are making use of the **Set.delete\_if() method**. This method is deleting all the elements from the Set if the set is having more elements than the requirement of the user. The condition is put inside an if condition; if that condition comes out to be true then the whole set will be deleted otherwise there will be no effect on the set.

在上面的代码中，您可以观察到我们正在使用**Set.delete\_if()方法** 。 如果集合中的元素数超过了用户的要求，则此方法将从集合中删除所有元素。 该条件放在if条件内； 如果该条件成立，则整个集合将被删除，否则对集合没有影响。

## keep\_if()方法 **(**keep\_if() method**)** ##

This method is just the opposite of the **Set.delete\_if() method**. This method will keep the set if the condition comes out to be true or you can say that it will delete all the elements of the Set if the condition comes out to be false.

该方法与**Set.delete\_if()方法**相反。 如果条件为真，则此方法将保留集合，或者可以说如果条件为假，则它将删除Set的所有元素。

This method does not take any arguments. If will return self and if no block is specified, it will return an enumerator.

此方法不带任何参数。 如果将返回self并且如果未指定任何块，则它将返回一个枚举数。

**Example:**

**例：**

=begin
    Ruby program to implement keep_if?().
    =end
    
    require 'set'
    
    Vegetable=Set.new(["potato","brocolli","broccoflower","lentils","peas","fennel","chilli","cabbage"])
    
    puts "Enter the number of element you want in the Set:"
    num = gets.chomp.to_i
    
    if Vegetable.count < num
    	Vegetable.keep_if()
    	puts "Set is not overloaded"
    else
    	puts "Set is overloaded"
    end

**Output**

**输出量**

RUN 1:
    Enter the number of element you want in the Set:
     12
    Set is not overloaded
    
    RUN 2:
    Enter the number of element you want in the Set:
     2
    Set is overloaded

**Example:**

**例：**

In the above code, you can observe that we are making use of the **Set.keep\_if() method**. This method is deleting all the elements from the Set if the set is having more elements than the requirement of the user. The condition is put inside if condition; if that condition comes out to be false then the whole set will be deleted otherwise there will be no effect on the set.

在上面的代码中，您可以观察到我们正在使用**Set.keep\_if()方法** 。 如果集合中的元素数超过了用户的要求，则此方法将从集合中删除所有元素。 条件被放入条件中； 如果该条件为假，则整个集合将被删除，否则对集合没有影响。

> 翻译自: [https://www.includehelp.com/ruby/set-methods-delete\_if-and-keep\_if.aspx][https_www.includehelp.com_ruby_set-methods-delete_if-and-keep_if.aspx]

ruby end if

[https_www.includehelp.com_ruby_set-methods-delete_if-and-keep_if.aspx]: https://www.includehelp.com/ruby/set-methods-delete_if-and-keep_if.aspx