总计在Ruby数组

Question

我正在尝试执行一个程序，要求用户每次输入一个三位数字，将它们存储在数组中，然后打印出数字和总数的列表。

请解释。

这是我到目前为止有：

numbers = Array.new 
numbers = [] 
puts "Enter first number: " 
first = gets.to_i 
puts "Enter second number: " 
second = gets.to_i 
puts "Enter third number: " 
third = gets.to_i 
def sum(numbers) 
    return 0 if numbers.length < 1 
    result = 0 
    numbers.each { |num| result += num } 
    result 
end 

Answer 1

你也可以使用Array的reduce方法。

http://ruby-doc.org/core-2.1.0/Enumerable.html#method-i-reduce

#!/usr/bin/ruby 
numbers = Array.new 
# numbers = [] #this is same as above 
puts "Enter first number: " 
first = gets.to_i 
numbers<<first 
puts "Enter second number: " 
second = gets.to_i 
numbers<<second 
puts "Enter third number: " 
third = gets.to_i 
numbers<<third 
puts numbers.reduce {|sum, n| sum + n } #here 

Answer 2

您还没有推你的任何投入的数组，你可以使用推送功能或< <将元素添加到您的阵列

#!/usr/bin/ruby 
numbers = Array.new 
numbers = [] 
puts "Enter first number: " 
first = gets.to_i 
numbers<<first 
puts "Enter second number: " 
second = gets.to_i 
numbers<<second 
puts "Enter third number: " 
third = gets.to_i 
numbers<<first 
def sum(someArray) 
    return 0 if someArray.length < 1 
    result = 0 
    someArray.each { |num| result += num } 
    result 
end 

希望帮助

Answer 3

这里有两个问题：

1. 您还没有推你读的数字为
2. 您正确定义的sum功能的阵列，但不调用它的任何地方

#!/usr/bin/ruby 
numbers = Array.new # note the second, redundant, initialization on numbers was removed 
puts "Enter first number: " 
(numbers ||= []) << gets.to_i # Pushing read value into the array (issue 1) 
puts "Enter second number: " 
(numbers ||= []) << gets.to_i # Here too 
puts "Enter third number: " 
(numbers ||= []) << gets.to_i # And here too 
def sum(numbers) 
    return 0 if numbers.length < 1 
    result = 0 
    numbers.each { |num| result += num } 
    result 
end 

puts sum(numbers) # Calling sum (issue 2) 

Answer 4

这里是这样做的另一种方式：

sum = 3.times.collect{ |i| puts "Enter number #{i + 1}:"; gets.chomp.to_i }.inject(:+) 
puts sum 

也可以这样写如下：

read_num = lambda{|i| puts "Enter number #{i}"; gets.chomp.to_i} 
sum = 3.times.map(&read_num).reduce(:+) 
puts sum