ruby推送示例_Ruby for循环示例

ruby推送示例

for循环 (The for loop)

In programming, for loop is a kind of iteration statement which allows the block to be iterated repeatedly as long as the specified condition is not met or a specific number of times that the programmer knows beforehand. A for loop is made of two parts:

在编程中， for循环是一种迭代语句，只要不满足指定条件或程序员事先知道的特定次数，就可以重复迭代该块。 for循环由两部分组成：

The header part
标头部分
The actual body
实际的身体

The header part is used to specify the number of iterations. Most of the times it explicitly mentions the count of iterations with the help of a variable. for loop is generally used when the number of iterations is explicitly known before the execution of the statement declared within its block. The actual body contains the expressions or statements which will be implemented once per repetition.

标头部分用于指定迭代次数。在大多数情况下，它借助变量明确提及迭代次数。当在其块内声明的语句执行之前明确知道迭代次数时，通常使用for循环 。实际主体包含将重复执行一次的表达式或语句。

It is a kind of Entry control loop. Generally, you can easily make an infinite loop through for loop by using the following syntax:

这是一种Entry控制循环。通常，您可以使用以下语法轻松地通过for循环进行无限循环：

    for(;;)
{
#body
}

In Ruby, for loop is implemented with the help of the following syntax:

在Ruby中， for循环是通过以下语法实现的：

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

Example 1:

范例1：

=begin
Ruby program to print the table of the number 
specified by the user using for loop	
=end
puts "Enter a number"
num=gets.chomp.to_i
for i in 1..10 		#implementation of for loop for 
#pre-specified range 1..10
k=i*num
puts "#{num} * #{i}  = #{k}"
i+=1		#incrementing the counter variable
end

Output

输出量

Enter a number
89
89 * 1  = 89
89 * 2  = 178
89 * 3  = 267
89 * 4  = 356
89 * 5  = 445
89 * 6  = 534
89 * 7  = 623
89 * 8  = 712
89 * 9  = 801
89 * 10  = 890

Example 2:

范例2：

=begin
Ruby program to print the list of the odd and even 
numbers where the lower limit is specified by the user 
and the upper limit is 100 using for loop		
=end
puts "Enter the lower limit(ul is 100)"
num=gets.chomp.to_i
if (num>=100)    #lower limit can not be 
#equal to or greater than upper limit 
puts "Invalid lower limit"
else
for i in num..100 #implementation of for loop for 
#pre-specified range num..100
if (i%2==0)
puts "#{i} is even"
else
puts "#{i} is odd"
end
i=i+1 	#incrementing the counter variable
end
end

Output

输出量

First run:
Enter the lower limit
76
76 is even
77 is odd
78 is even
79 is odd
80 is even
81 is odd
82 is even
83 is odd
84 is even
85 is odd
86 is even
87 is odd
88 is even
89 is odd
90 is even
91 is odd
92 is even
93 is odd
94 is even
95 is odd
96 is even
97 is odd
98 is even
99 is odd
100 is even
Second run:
Enter the lower limit
900
Invalid lower limit

The for loop is one of the most commonly used loops in programming. As it is preferable and has easy syntax.

for循环是编程中最常用的循环之一。最好是它并且语法简单。