ruby and 语句_在Ruby中重做和重试语句

灰太狼 2023-03-05 10:59 23阅读 0赞

ruby and 语句

## Ruby重做和重试语句 **(**Ruby redo and retry statements**)** ##

Ruby is a very flexible language; it provides you many ways through which you can make your code more effective and clear. With the help of redo and retry statement, you can make your code more readable to the user as well as you can perform functionalities more efficiently. Let us go through the syntax, area of implementation and example of each of the statements.

Ruby是一种非常灵活的语言。 它为您提供了许多使代码更有效和更清晰的方法。 借助重做和重试语句，可以使代码对用户更易读，并且可以更有效地执行功能。 让我们仔细阅读每个语句的语法，实现区域和示例。

### 1)Ruby重做语句 **(**1) Ruby redo statement **)** ###

**redo statement** comes into the scene when you have to re-execute the iteration in the same loop. It repeats the current iteration in the loop. The feature of the **redo statement** is that it executes without even evaluating the loop condition. Sometimes, this results in the creation of an infinite loop. Let us see the syntax and examples.

当您必须在同一循环中重新执行迭代时， **重做语句**就会出现。 它在循环中重复当前的迭代。 **重做语句**的功能是它执行时甚至不评估循环条件。 有时，这会导致创建无限循环。 让我们看一下语法和示例。

**Syntax:**

**句法：**

while (#condition)
            #statements
            redo if  #condition
        end

**Example 1:**

**范例1：**

=begin
    Ruby program to demonstrate redo 
    =end
    
    i = 30   
    
    while(i < 50)      
        puts "Value of i is #{i}"   
        i += 1   
        redo if i == 50
    end

**Output**

**输出量**

Value of i is 30
    Value of i is 31
    Value of i is 32
    Value of i is 33
    Value of i is 34
    Value of i is 35
    Value of i is 36
    Value of i is 37
    Value of i is 38
    Value of i is 39
    Value of i is 40
    Value of i is 41
    Value of i is 42
    Value of i is 43
    Value of i is 44
    Value of i is 45
    Value of i is 46
    Value of i is 47
    Value of i is 48
    Value of i is 49
    Value of i is 50

**Explanation:**

**说明：**

In the above code, you can see that the condition specified in the [while loop][] tells the iteration to be done up to **49** but due to the introduction of **redo statement** the iteration is going up to **50** because **redo statement** executes before the condition is checked.

在上面的代码中，您可以看到[while循环中][while loop]指定的条件告诉迭代最多可以完成**49次，**但是由于引入了**redo语句，**因此迭代最多可以进行**50次，**因为**redo语句**在检查条件之前执行。

**Example 2:**

**范例2：**

=begin
    Ruby program to demonstrate redo 
    =end
    
    i = 30   
    
    while(i < 50)      
        puts "Value of i is #{i}"   
        i += 1   
        redo if i > 45
    end

**Output**

**输出量**

An infinite loop

**Explanation:**

**说明：**

The above code will give an infinite loop because i will always be greater than **45**.

上面的代码将给出一个无限循环，因为我将始终大于**45** 。

### 2)Ruby重试语句 **(**2) Ruby retry statement**)** ###

In Ruby, the **retry statement** only works inside the begin/rescue block. You can also say that it works in the context of [exception handling][]. You should use a **retry statement** when you want to re-execute the block.

在Ruby中， **retry语句**仅在begin / rescue块内起作用。 您也可以说它在[异常处理][exception handling]的上下文中起作用。 要重新执行该块时，应使用**retry语句** 。

**Syntax:**

**句法：**

retry

**Example:**

**例：**

=begin
    Ruby program to demonstrate retry 
    =end
    
    for i in 0..10
    	begin
    		puts "VALUE OF i #{i}"
    		raise if i >=9
    		rescue
    		retry
    	end
    end

**Output**

**输出量**

Infinite loop.

**Explanation:**

**说明：**

This will also give an infinite loop because exception will be raised until i>=9 and this is an infinite situation.

这也将产生无限循环，因为将引发异常，直到i> = 9 ，这是无限情况。

> 翻译自: [https://www.includehelp.com/ruby/redo-and-retry-statements.aspx][https_www.includehelp.com_ruby_redo-and-retry-statements.aspx]

ruby and 语句

[while loop]: https://www.includehelp.com/ruby/while-loop.aspx
[exception handling]: https://www.includehelp.com/ruby/exception-handling-in-ruby.aspx
[https_www.includehelp.com_ruby_redo-and-retry-statements.aspx]: https://www.includehelp.com/ruby/redo-and-retry-statements.aspx