在文本文件中的n行之后触发循环

Question

如果在要写入的文本文件中只执行了5行，我想执行一个循环。原因是，我希望从文本文件的最后5行计算平均值，如果程序没有5个数字可供使用，则会抛出一个rumtime错误。

    #Imports
    from bs4 import BeautifulSoup
    from urllib import urlopen
    import time
    #Required Fields
    pageCount = 1290429

    #Loop
    logFile = open("PastWinners.txt", "r+")
    logFile.truncate()
    while(pageCount>0): 
        time.sleep(1)
        html = urlopen('https://www.csgocrash.com/game/1/%s' % (pageCount)).read()
        soup = BeautifulSoup(html, "html.parser")
        try:
            section = soup.find('div', {"class":"row panel radius"})
            crashPoint = section.find("b", text="Crashed At: ").next_sibling.strip()
            logFile.write(crashPoint[0:-1]+"n")
        except:
            continue
        for i, line in enumerate(logFile):             #After 5 lines, execute this
            if i > 4:
                data = [float(line.rstrip()) for line in logFile]
                print("Average: " + "{0:0.2f}".format(sum(data[-5:])/len(data[-5:])))
            else:
                continue
        print(crashPoint[0:-1])
        pageCount+=1
    logFile.close()
If anyone knows the solution, or knows a better way to go about doing this, it would be helpful, thanks :).

编辑：

更新代码：

#Imports
from bs4 import BeautifulSoup
from urllib import urlopen
import time
#Required Fields
pageCount = 1290429
lineCount = 0
def FindAverage():
    with open('PastWinners.txt') as logFile:
        data = [float(line.rstrip()) for line in logFile]
        print("Average: " + "{0:0.2f}".format(sum(data[-5:])/len(data[-5:])))
#Loop
logFile = open("PastWinners.txt", "r+")
logFile.truncate()
while(pageCount>0): 
    time.sleep(1)
    html = urlopen('https://www.csgocrash.com/game/1/%s' % (pageCount)).read()
    soup = BeautifulSoup(html, "html.parser")
    if lineCount > 4:
        logFile.close()
        FindAverage()
    else:
        continue
    try:
        section = soup.find('div', {"class":"row panel radius"})
        crashPoint = section.find("b", text="Crashed At: ").next_sibling.strip()
        logFile.write(crashPoint[0:-1]+"n")
    except:
        continue
    print(crashPoint[0:-1])
    pageCount+=1
    lineCount+=1

logFile.close()

新问题：程序按预期运行，但一旦计算并显示平均值，程序就不会再次循环，而是停止。我希望它能工作，所以在5行之后，它会计算平均值，然后显示下一个数字，然后显示新的平均值，以此类推

您的while循环永远不会结束。我想你是想减少：pageCount-=1。

最后的问题是循环没有重新启动，只是完成了第一次平均值计算。这是由于logFile被关闭而没有重新打开，所以程序考虑了这一点，并将其附加到文件中，它的工作与预期的一样。感谢大家的帮助。

#Imports
from bs4 import BeautifulSoup
from urllib import urlopen
import time
#Required Fields
pageCount = 1290429
lineCount = 0
def FindAverage():
    with open('PastWinners.txt') as logFile:
        data = [float(line.rstrip()) for line in logFile]
        print("Average: " + "{0:0.2f}".format(sum(data[-5:])/len(data[-5:])))
#Loop
logFile = open("PastWinners.txt", "r+")
logFile.truncate()
while(pageCount>0):
    time.sleep(1)
    html = urlopen('https://www.csgocrash.com/game/1/%s' % (pageCount)).read()
    soup = BeautifulSoup(html, "html.parser")
    try:
        section = soup.find('div', {"class":"row panel radius"})
        crashPoint = section.find("b", text="Crashed At: ").next_sibling.strip()
        logFile.write(crashPoint[0:-1]+"n")
    except:
        continue
    print(crashPoint[0:-1])
    pageCount+=1
    lineCount+=1
    if lineCount > 4:
        logFile.close()
        FindAverage()
        logFile = open("PastWinners.txt", "a+")
    else:
        continue
logFile.close()