ruby 嵌套函數

嵌套循環 (Nested for loop)

Nesting of for loop means one for loop is available inside another for loop. It means that there are two loops, then the first one is an outer loop and the second one is the inner loop. Execution will take place in the manner that first the outer for loop is triggered, then if the condition is matched the pointer will be passed to the inner loop. Here also if the condition is satisfied, the inner for loop body will be executed until specified condition does not comes out to be false. Once the inner loop completes its execution, the pointer will be passed back to the outer for loop for its successful execution.

嵌套for循環意味著一個for循環可在另一個for循環內使用 。 這意味著有兩個循環，然后第一個是外部循環，第二個是內部循環。 執行將以首先觸發外部for循環的方式進行，然后如果條件匹配，則指針將被傳遞到內部循環。 同樣，如果滿足條件，則將執行內部for循環主體，直到指定條件不為假為止。 內部循環完成執行后，指針將被傳遞回外部for循環以成功執行。

In Ruby, Nesting of for loop can be done with the help of the following syntax:

在Ruby中，可以使用以下語法來完成for循環的嵌套 ：

    for variable_name[, variable...] in expression [do]
#expressions
for variable_name[, variable...] in expression [do]
# code to be executed
end
#expressions
end

Example 1:

范例1：

=begin 
Ruby program to demonstrate nested for loop
=end
puts "Enter upper limit"
ul=gets.chomp.to_i
puts "Enter Lower limit"
ll=gets.chomp.to_i
for i in ll..ul do
for i in 0..3 do
puts "Inner loop triggered"
end
puts "Outer loop triggered"
end

Output

輸出量

Enter upper limit
90
Enter Lower limit
85
Inner loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Outer loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Outer loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Outer loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Outer loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Outer loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Inner loop triggered
Outer loop triggered

You can observe in the above example that first the outer for loop is invoked then the pointer has moved to inner loop and it is printing the message for times.

您可以在上面的示例中觀察到，首先調用了外部for循環，然后指針移至了內部循環，并且多次打印該消息。

Once the inner for loop completes its task, the pointer goes back to the outer loop.

內部for循環完成其任務后，指針將返回到外部循環。

Example 2:

范例2：

Patterns can also be printed using nested for loop. Now let us have a quick view of how the following pattern can be printed.

也可以使用嵌套的for循環來打印圖案。 現在讓我們快速了解如何打印以下圖案。

*
**
***
****
*****

Code:

碼：

=begin 
Ruby program to print a pattern using nested for loop
=end
for i in 1..5 do
for j in 1..i do
print "*"
end
puts ""
end

翻譯自: https://www.includehelp.com/ruby/nested-for-loop-with-examples.aspx

ruby 嵌套函數