總計在Ruby數組

Question

我正在嘗試執行一個程序，要求用戶每次輸入一個三位數字，將它們存儲在數組中，然後打印出數字和總數的列表。

請解釋。

這是我到目前爲止有：

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

您還沒有推你的任何投入的數組，你可以使用推送功能或< <將元素添加到您的陣列

#!/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 

希望幫助

Answer 3

這裏有兩個問題：

1. 您還沒有推你讀的數字爲
2. 您正確定義的sum功能的陣列，但不調用它的任何地方

#!/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

這裏是這樣做的另一種方式：

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

也可以這樣寫如下：

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