python - 平均功能不是平均而是重置

Question

我正在尝试利用 TeamTreehouse 学习订阅和这本《从编程逻辑和设计开始》一书来尝试学习编程和 Python。

目标:合并第 12 行中通过引用传递接收到的输入，然后将传入 testScoreAverage 的每个后续输入添加到先前的值中。相反，它只是保留一个值而不是运行总计。

我添加了注释，逐行表明我的错误/对代码的理解

我真的认为我以某种方式通过将变量设置为数据类型 int 来将它们设置为 0，但我不明白这是怎么回事，因为我过去已经能够做到这一点？

#///////////////Defining Variables/////////////
testScore1=0
testScore2=0
testScore3=0
testScore4=0
testScore5=0
tests=5
testScoreAverage=0
#///////////////Defining Variables/////////////

#///////////////calcAverage Function/////////////

#L2g2h: defines function & receives current testScore int value
def calcAverage(testScore):

    #L2g2h: initiates variable testScoreAverage as an int value type (but doesn't set it to any value)
    testScoreAverage=int()

    #L2g2h: again initiating a variable, variable testScores, to int value type (but not setting it to any numeric value)
    testScores=int()

    #L2g2h: for loop starting
    for i in range(1, tests + 1):

        #L2g2h: testScores is set equal to the current testScores value PLUS the current value of testScore to become a running total
        testScores=testScores+testScore

        #L2g2h: testScoreAverage is dividing the current testScores value by the current counter variable i's value to come up with an average
        testScoreAverage=testScores/i

    #////NEED TO SET NUMBER TO HOLD ONLY 2 DECIMAL PLACES
    #L2g2h: print out the current testScoreAverage
    print("Your test score average so far is ", float(testScoreAverage))

#///////////////calcAverage Function/////////////

#///////////////determineGrade Function/////////////    
def determineGrade(testScore):
#    for i in range(1, tests + 1):     
    if testScore>=90 and testScore <= 100:
        print("Your test score grade is an A.")
    elif testScore>=80 and testScore <= 89:
        print("Your test score grade is a B.")
    elif testScore>=70 and testScore <= 79:
        print("Your test score grade is a C.")
    elif testScore>=60 and testScore <= 69:
        print("Your test score grade is a D.")
    elif testScore<=60:
        print("Your test score grade is a F.")
    else:
        print("That is invalid.")
#///////////////determineGrade Function/////////////
for i in range(1, tests + 1):
    testScore=int(input("Enter test score #" + str(i)))
    calcAverage(testScore)
    determineGrade(testScore)

Answer 1

您在最后一个 for 循环中的每次迭代中调用函数 calcAverage 一次。只有在用户输入所有分数值后才应计算平均值。

首先将您的值附加到列表中，然后在用户输入所有值后计算平均值:

#///////////////Defining Variables/////////////
testScore1=0
testScore2=0
testScore3=0
testScore4=0
testScore5=0
tests=5
testScoreAverage=0
#///////////////Defining Variables/////////////

#///////////////calcAverage Function/////////////
def calcAverage(testScore):
    testScoreAverage=int()
    testScoreAverage= sum(testScore)/len(testScore)
#////NEED TO SET NUMBER TO HOLD ONLY 2 DECIMAL PLACES
    print("Your test score average so far is ", float(testScoreAverage))
    return testScoreAverage
#///////////////calcAverage Function/////////////

#///////////////determineGrade Function/////////////    
def determineGrade(testScore):
#    for i in range(1, tests + 1):     
    if testScore>=90 and testScore <= 100:
        print("Your test score grade is an A.")
    elif testScore>=80 and testScore <= 89:
        print("Your test score grade is a B.")
    elif testScore>=70 and testScore <= 79:
        print("Your test score grade is a C.")
    elif testScore>=60 and testScore <= 69:
        print("Your test score grade is a D.")
    elif testScore<=60:
        print("Your test score grade is a F.")
    else:
        print("That is invalid.")
#///////////////determineGrade Function/////////////

scores =[]
for i in range(1, tests + 1):
    scores.append(int(input("Enter test score #" + str(i)+" ")))

average = calcAverage(scores)
determineGrade(average)

请注意，要计算列表中的平均值，您可以使用 sum 函数对该列表中的所有值求和，然后使用 len(list)< 除以列表长度

如果您想确定每个分数的等级，您可以迭代包含分数的列表并确定每个分数的等级，如下所示:

for score in scores: #scores is the list
    determineGrade(score)