Ruby嵌套每個循環

Question

我想通過讓程序工作來理解嵌套循環。如果可能的話，我想使用循環的「每個做法」。現在循環執行所有的第一個循環，然後第二個......等等......我想要做的是，執行第一個循環1次，然後一次下降到第二個循環......等等。這裏是我的代碼（粘貼以下）

期望輸出會是這樣的：

index      3.0     3.0 
+-------------------------------------------------------+ 
0       -23.4    -23.4 
1      -2226.74    -2226.74 
2     -1.93464e+07   -1.93464e+07 

代碼

class LogisticsFunction 
    puts "Enter two numbers, both between 0 and 1 (example: .25 .55)." 
    puts "After entering the two numbers tell us how many times you" 
    puts "want the program to iterate the values (example: 1)." 

    puts "Please enter the first number: " 
    num1 = gets.chomp 

    puts "Enter your second number: " 
    num2 = gets.chomp 

    puts "Enter the number of times you want the program to iterate: " 
    iter = gets.chomp 

    print "index".rjust(1) 
    print num1.rjust(20) 
    puts num2.rjust(30) 
    puts "+-------------------------------------------------------+" 

    (1..iter.to_i).each do |i| 
    print i 
    end 
    (1..iter.to_i).each do |i| 
     num1 = (3.9) * num1.to_f * (1-num1.to_f) 
     print num1 
    end 
     (1..iter.to_i).each do |i| 
     num2 = (3.9) * num2.to_f * (1-num2.to_f) 
      print num2 
     end 
end 

Answer 1

我覺得你不必有三個循環中運行，下面將給願望輸出

(1..iter.to_i).each do |i| 
    print i 
    num1 = (3.9) * num1.to_f * (1-num1.to_f) 
    print num1.to_s.rjust(20) 
    num2 = (3.9) * num2.to_f * (1-num2.to_f) 
    print num2.to_s.rjust(30) 
end 

Answer 2

難道不這樣的事情解決問題了嗎？

(1..iter.to_i).each do |i| 
    num1 = (3.9) * num1.to_f * (1-num1.to_f) 
    print num1 
    num2 = (3.9) * num2.to_f * (1-num2.to_f) 
    print num2 
end 

從我能看到你甚至不使用i變量。所以從理論上講，你可以只是做

iter.to_i.times do 
    # stuff 
end 

Answer 3

您的循環實際上並沒有嵌套。它們實際上是一個接一個的。這就是爲什麼他們一個接一個地運行。要嵌套它們 - 你必須把它們放在彼此之內。例如：

沒有嵌套

(1..iter.to_i).each do |i| 
    # stuff for loop 1 is done here 
end # this closes the first loop - the entire first loop will run now 

(1..iter.to_i).each do |j| 
    # stuff for loop 2 is done here 
end # this closes the second loop - the entire second loop will run now 

嵌套：

(1..iter.to_i).each do |i| 
    # stuff for loop 1 is done here 
    (1..iter.to_i) .each do |j| 
    # stuff for loop 2 is done here 
    end # this closes the second loop - the second loop will run again now 
    # it will run each time the first loop is run 
end # this closes the first loop - it will run i times