Question

我想将while循环应用到下面的for循环中。我已经尝试在每个if语句中将if循环放在if语句之前。当我把它放在if语句之前（在for循环中）时，它会询问用户一次，然后返回整个范围的相同输入（1,8）。我希望这个while循环适用于每个问题，七个项目2到8 我该如何实现它。任何人都可以帮忙，谢谢

def valid_entry ():
    price = 110
    invalid_input = 1
    while price< 0 or price> 100:
        if invalid_input >=2:
            print "This is an invalid entry"
            print "Please enter a number between 0 and 100"
        try:
            price= int(raw_input("Please enter your price  : "))
        except ValueError:
            price = -1   
        invalid_input +=1

while循环结束

def prices ():   
    x = range (1,8)
    item=2
    price=0
    for item in x:
        item +=1
        print "\n\t\titem",item
        price = int(raw_input("Enter your price : "))
        if price <10:
            price=1
            print "This is ok"


        if price >9 and price <45:
            price +=5
            print "This is great"


        if price >44 and price <70:
            price +=15
            print "This is really great"

        if price >69:
            price +=40
            print "This is more than i expected"

    print "\nYou now have spent a total of ",price

prices ()

缺乏回应是否表明这是一个愚蠢的问题，还是不可能做到？

这会让它更清楚吗？

def prices ():   
    x = range (1,8)
    item=2
    price=0
    for item in x:
        item +=1
        print "\n\t\titem",item
        valid_entry ()#should it go here
        price = int(raw_input("Enter your price : "))
        valid_entry ()#should it go here
        if price <10:
           valid_entry ()#should it go here and so on for the following 3 if conditions
            price=1
            print "This is ok"


        if price >9 and price <45:
            price +=5
            print "This is great"


        if price >44 and price <70:
            price +=15
            print "This is really great"

        if price >69:
            price +=40
            print "This is more than i expected"

    print "\nYou now have spent a total of ",price

Answer 1

你可以尝试这样的事情（如果这不是你想要的，那就道歉）。很高兴解释任何没有意义的事情 - 总的想法是它循环通过8个项目的范围，每次要求有效价格并继续询问输入的值是否不是指定范围内的数字。由于这可能适用于作业，我试图将其与您已经证明的已知的概念保持一致（这里唯一的例外可能是continue）：

def valid_entry():
    # Here we define a number of attempts (which is what I think
    # you were doing with invalid_input). If the person enters 10
    # invalid attempts, the return value is None. We then check to
    # see if the value we get back from our function is None, and if
    # not, proceed as expected.
    num_attempts = 0
    while num_attempts < 10:
        # Here we do the input piece. Note that if we hit a ValueError,
        # the 'continue' statement skips the rest of the code and goes
        # back to the beginning of the while loop, which will prompt
        # again for the price.
        try:
            price = int(raw_input("Enter your price : "))
        except ValueError:
            print 'Please enter a number.'
            num_attempts += 1
            continue

        # Now check the price, and if it isn't in our range, increment
        # our attempts and go back to the beginning of the loop.
        if price < 0 or price > 100:
            print "This is an invalid entry"
            print "Please enter a number between 0 and 100"
            num_attempts += 1
        else:
            # If we get here, we know that the price is both a number
            # and within our target range. Therefore we can safely return
            # this number.
            return price

    # If we get here, we have exhausted our number of attempts and we will
    # therefore return 'None' (and alert the user this is happening).
    print 'Too many invalid attempts. Moving to the next item.'
    return None


def prices():
    # Here we go from 1-8 (since the upper bound is not included when
    # using range).
    x = range(1,9)

    # Here we use a variable (total) to store our running total, which will
    # then be presented at the end.
    total = 0

    # Now we iterate through our range.
    for item in x:
        print "\n\t\titem",item

        # Here is the important part - we call our valid_entry function and
        # store the result in the 'price' variable. If the price is not
        # None (which as we saw is the return value if the number of attempts
        # is > 10), we proceed as usual.
        price = valid_entry()
        if price is not None:
            if price <10:
                # Note this should probably be += 1
                total += 1
                print "This is ok"

            elif price >= 10 and price < 45:
                total += 5
                print "This is great"

            elif price >= 45 and price < 70:
                total += 15
                print "This is really great"

            # We know that price >= 70 here
            else:
                total += 40
                print "This is more than i expected"

    # Now print out the total amount spent
    print "\nYou now have spent a total of ", total

prices()

将while循环插入for循环

1 个答案: