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尝试从二维列表中查找平均变化率（从.txt文件读取）时，结果不正确

2017-03-27 28 views
0

我创建了一个程序，它将读取由价格列表组成的.txt文件。该计划将创建一个2维列表来存储周数，价格和前一周的变化。用户将输入所需的开始周和结束周。尝试从二维列表中查找平均变化率（从.txt文件读取）时，结果不正确

如果用户要输入的'开始一周为“1”和“端周”为“6”： 的平均变化应该是“-0.30” 的最高改变应该是“4周”随着变化'2.80' 最低变化应该是'第5周'与变化'-4.93'

但是，我的数字出来完全错误。

这里是我的代码：

# get two dimensional list 
priceList = [] 

#open the file 
priceFile = open ('MicrosoftPrices.txt', 'r') 

#create variable for start year 
week = 1 
price = float (priceFile.readline()) 

#special case for week 1 

#initialize loop counter 
i = 0 

while price != '': 
    priceList.append ([0,0,0]) 

    priceList [i][0] = week 
    priceList [i][1] = float (price) 

    if week == 1: 
     priceList [i][2] = 0 
    else: 
     priceList[i][2] = ((priceList[i][1] - priceList[i-1][1])/priceList[i-1][1]) 

    #read the next line 
    price = priceFile.readline() 

    #add to the counter 
    i += 1 

    #go to next week 
    week = week + 1 

#initialize start and end weeks 
startWeek = 0 
endWeek = 0 

#define start week validation 
def FirstValidation (startWeek): 

    startWeek = -1 

    while startWeek == -1: 
     startWeek = input ('What week would you like to start with?') 

     try: 
      if startWeek == '': 
       startWeek = 1 
       break 

      startWeek = int (startWeek) 

     except Exception: 
      print ('Year must be a valid integer between 1 and 52') 

     else: 
      if startWeek >= 1 and startWeek <= 52: 
       break 
      else: 
       startWeek = -1 
       print ('ERROR: Week must be a valid integer between 1 and 52! Please try again.') 

    return startWeek 

#define end week validation 
def LastValidation (endWeek): 
    endWeek = -1 

    while endWeek == -1: 
     endWeek = input ('What week would you like to end with?') 

     try: 
      if endWeek == '': 
       endWeek = 52 
       break 

      endWeek = int (endWeek) 

     except Exception: 
      print ('Year must be a valid integer between 1 and 52') 
     else: 
      if endWeek >= startWeek and endWeek <= 52: 
       break 
      else: 
       endWeek = -1 
       print ('ERROR: Week must be a valid integer between 1 and 52! Please try again.') 

    return endWeek 

def main(): 

    #call week validations 
    startWeekVal = FirstValidation ('Start Week') 
    endWeekVal = LastValidation ('End Week') 


    #initialize min and max 
    maxChange = 0 
    minChange = 100 
    maxIndex = 0 
    minIndex = 0 
    total = 0 
    count = 0 

    for j in range (startWeekVal, endWeekVal +1): 
     if priceList [j][2] > maxChange: 
      maxChange = priceList [j][2] 
      maxIndex = j 
     if priceList [j][2] < minChange: 
      minChange = priceList [j][2] 
      minIndex = j 

     #calc average 
     total += priceList [j][2] 
     count += 1 

     #compute average 
     average = total/count 

    print ('Start Week:', startWeekVal) 
    print ('End Week:', endWeekVal) 
    print ('The average change is ', average) 
    print ('The week with the highest change is week' , priceList [maxIndex][0], 'with $', format (maxChange, '.2f')) 
    print ('The week with the lowest change is week' , priceList [minIndex][0], 'with $', format (minChange, '.2f')) 

    #close the file 
    priceFile.close() 

#call main 
main()

仅供参考，这里是.txt文件：

52.33 
50.99 
52.29 
55.09 
50.16 
50.50 
51.82 
51.30 
52.03 
53.07 
53.49 
54.21 
55.57 
54.42 
55.65 
51.78 
49.87 
50.39 
51.08 
50.62 
52.32 
51.79 
51.48 
50.13 
49.83 
51.16 
52.30 
53.70 
56.57 
56.68 
57.96 
57.94 
57.62 
58.03 
57.67 
56.21 
57.25 
57.43 
57.60 
57.80 
57.42 
59.66 
59.87 
58.71 
59.02 
60.35 
60.53 
59.25 
61.97 
62.30 
63.24 
62.14

来源

2017-03-27 Jeremy Mosier

+0

应该在两周之间的变化是价值观的差异？你为什么分裂？ –

+0

你是对的，我刚刚解决了这个问题。我现在正在获取正确的最小值和最大值。仍然没有得到正确的平均变化率。 –

+0

您对平均变化率有什么价值？ –

回答

1

这段代码，我想，应该做你想要什么：

# get two dimensional list 
priceList = [] 

#open the file 
priceFile = open ('MicrosoftPrices.txt', 'r') 

#create variable for start year 
week = 1 
price = float (priceFile.readline()) 

#special case for week 1 

#initialize loop counter 
i = 0 

while price != '': 
    priceList.append ([0,0,0]) 

    priceList [i][0] = week 
    priceList [i][1] = float (price) 

    if week == 1: 
     priceList [i][2] = 0 
    else: 
     priceList[i][2] = (priceList[i][1] - priceList[i-1][1]) 

    #read the next line 
    price = priceFile.readline() 

    #add to the counter 
    i += 1 

    #go to next week 
    week = week + 1 

#initialize start and end weeks 
startWeek = 0 
endWeek = 0 

#define start week validation 
def FirstValidation (startWeek): 

    startWeek = -1 

    while startWeek == -1: 
     startWeek = input ('What week would you like to start with?') 

     try: 
      if startWeek == '': 
       startWeek = 1 
       break 

      startWeek = int (startWeek) 

     except Exception: 
      print ('Year must be a valid integer between 1 and 52') 

     else: 
      if startWeek >= 1 and startWeek <= 52: 
       break 
      else: 
       startWeek = -1 
       print ('ERROR: Week must be a valid integer between 1 and 52! Please try again.') 

    return startWeek 

#define end week validation 
def LastValidation (endWeek): 
    endWeek = -1 

    while endWeek == -1: 
     endWeek = input ('What week would you like to end with?') 

     try: 
      if endWeek == '': 
       endWeek = 52 
       break 

      endWeek = int (endWeek) 

     except Exception: 
      print ('Year must be a valid integer between 1 and 52') 
     else: 
      if endWeek >= startWeek and endWeek <= 52: 
       break 
      else: 
       endWeek = -1 
       print ('ERROR: Week must be a valid integer between 1 and 52! Please try again.') 

    return endWeek 

def main(): 

    #call week validations 
    startWeekVal = FirstValidation ('Start Week') 
    endWeekVal = LastValidation ('End Week') 


    #initialize min and max 
    maxChange = 0 
    minChange = 100 
    maxIndex = 0 
    minIndex = 0 
    total = 0 
    count = 0 

    print priceList 

    for j in range (startWeekVal-1, endWeekVal): 
     if priceList [j][2] > maxChange: 
      maxChange = priceList [j][2] 
      maxIndex = j 
     if priceList [j][2] < minChange: 
      minChange = priceList [j][2] 
      minIndex = j 

     #calc average 
     total += priceList [j][2] 
     count += 1 

     #compute average 

    average = total/count 

    print ('Start Week:', startWeekVal) 
    print ('End Week:', endWeekVal) 
    print ('The average change is ', average) 
    print ('The week with the highest change is week' , priceList [maxIndex][0], 'with $', format (maxChange, '.2f')) 
    print ('The week with the lowest change is week' , priceList [minIndex][0], 'with $', format (minChange, '.2f')) 

    #close the file 
    priceFile.close() 

#call main 
main()

有几个问题，你迭代的范围增加了一个。这意味着如果你试图开始1周和结束2周，它实际上是2和3。然后，您试图跟踪每个子阵列的第三个条目中的更改百分比，然后再次对其进行平均。而是跟踪第三项的大小变化，然后在最后平均。

来源

2017-03-27 18:57:34 WillySchu

0

我会推荐这样的事情

def stats(y, start, stop): 
    maximum = max(y[start, stop]) 
    minimum = min(y[start, stop]) 
    average = sum(y[start, stop])/len(y[start, stop]) 
    return maximum, minimum, average 

with open('prices.txt') as f: 
    l = list(map(float, f.readlines())) 

x = l[0] 
y = [] 
for i in l: 
    y.append(i-x) 
    x=i 

#We now have two lists. l[i] has the price at week i, and 
    #y[i] has the change in price from week i-1 

start_week = int(input("Start Week: ")) -1 
end_week = int(input("End Week: ")) 

maximum, minimum, average = stats(y, start_week, end_week) 

print("Maximum {}".format(maximum)) 
print("Minimum {}".format(minimum)) 
print("Average {}".format(average))

来源

2017-03-27 19:02:21

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