Project Euler（Python）＃14 - 從「if」循環中提取數據

Question

這是question 14 in project euler，但我在創建循環時遇到了問題......但是拉出/計算了我從循環創建的數字。我目前正在通過PE學習如何使用python。

這裏我我的代碼以註釋：

import time # gets the time functionality 

start = time.time() # starts the timer 

def seq(x, count = 1): # This is a function, with the parameter of x and counting 

    seq = [x] # a data frame for the Collatz Sequence with x being placed in there 

    if x < 1: 

     return count 

    while x > 1: 

     count += 1 

     if x % 2 == 0: # determines if the number is even or not 

      x = x/2 

     else: 
      x = (3 * x) + 1 

    seq.append(count) # adds all the answers generated to the seq data fram 

max = [0,0] # define a new placeholder to "hold" the numbers you find, first[0] is number, and second[1] is length 

for i in range(10): 

    c = seq(i) 

    if c > max[0]: # if the length is > 0 put the new length here (below) 

     max[0] = c 
     max[1] = i # once you know the length is greater, you can put the value in the box as well 

elapsed = (time.time() - start) 

print "The program found the number %s has the longest length at %s, in %s seconds" % (max[1], max[0], elapsed) 

例如，當我把：

seq(10) 

我的輸出是：

[1, 1] 
[2, 2] 
[3, 8] 
[4, 3] 
[5, 6] 
[6, 9] 
[7, 17] 
[8, 4] 
[9, 20] 

隨着第一列是作爲數評估，其次是櫃檯。

然而，當我想提取使用max最大計數器（第二列）= [0,0]的數據幀，我不斷收到此錯誤：

The program found the number 0 has the longest length at 1, in 0.00015115737915 seconds 

但數字不能爲0和1，因爲輸出（上面）對於計數器的最大值爲20 ...所以文本輸出應該是9和20.

我可能不理解不同類型的數據，所以任何幫助表示讚賞。

Answer 1

你seq函數應該總是返回一個值，但現在它只有當x < 1.將return語句在年底返回的東西，太：

seq.append(count) # adds all the answers generated to the seq data fram 
return count