ValueError：以 10 为基数的 int() 的文字无效：'u'

Question

我无法将这两个值相乘。无论如何它都无法转换为整数。

tbl_breed = ["Red Chittagong", "Sussex", "Dexter", "Abondance",
             "Sahiwal", "Vorderwald", "Ayrshire", "Jersey",
             "Randall", "Alderney", "Carora", "Gloucester"]
tbl_rating = [1, 2, 3, 2, 3, 1, 2, 1, 2, 1, 3, 2]
tbl_count = [6, 3, 8, 7, 6, 4, 3, 7, 3, 3, 4, 7]
tbl_volume = [7.5, 5.7, 11.4, 11.4,
              22.0, 15.2, 21.0, 18.3,
              19.0, 9.0, 23.1, 16.0]
tbl_dailyVolume = []
dailyvol = 0


x = 0
while x <12:
    totallist = [tbl_breed[x], tbl_rating[x], tbl_count[x], tbl_volume[x]]
    x = x + 1

    print(totallist)

for total in totallist:
    namebreed = total[0]
    rating = total[1]
    numcows = total[2]
    volmilk = total[3]

    volmik = int(float(volmilk))
    
    dailyvol = (numcows * volmilk)
    print(namebreed, ":", dailyvol)

错误是：

Traceback (most recent call last):
  File "/Users/squatpapa/Desktop/june2023 mock comp sci/Q06.py", line 30, in <module>
    volmik = int(float(volmilk))
ValueError: could not convert string to float: 'u'

我只是想将值相乘来找到总数，然后在每个列表中的前一个值旁边循环打印它们并输出。

Answer 1

在第一个循环结束时，

totallist

是

['Gloucester', 2, 7, 16.0]

。您应该亲眼看到这一点，因为循环中有

print(totallist)

。

然后第二个循环迭代该列表中的每个项目。

total

在第一次迭代时变为

'Gloucester'

，因此

namebread

是该字符串的第一个元素（字母

'G'

），

rating

是该字符串的第二个元素（字母

'l')

，等等）开。

volmilk

是该字符串的第四个元素，字母

'u'

。

Answer 2

你只需要在

totallist

中制作一个列表：

tbl_breed = ["Red Chittagong", "Sussex", "Dexter", "Abondance",
             "Sahiwal", "Vorderwald", "Ayrshire", "Jersey",
             "Randall", "Alderney", "Carora", "Gloucester"]
tbl_rating = [1, 2, 3, 2, 3, 1, 2, 1, 2, 1, 3, 2]
tbl_count = [6, 3, 8, 7, 6, 4, 3, 7, 3, 3, 4, 7]
tbl_volume = [7.5, 5.7, 11.4, 11.4,
              22.0, 15.2, 21.0, 18.3,
              19.0, 9.0, 23.1, 16.0]
tbl_dailyVolume = []
dailyvol = 0

totallist = [[breed, rating, count, volume] for (breed, rating, count, volume) in zip(tbl_breed, tbl_rating, tbl_count, tbl_volume)]


for total in totallist:
    namebreed = total[0]
    rating = total[1]
    numcows = total[2]
    volmilk = total[3]

    volmik = int(float(volmilk))
    
    dailyvol = (numcows * volmilk)
    print(namebreed, ":", dailyvol)

输出：

Red Chittagong : 45.0
Sussex : 17.1
Dexter : 91.2
Abondance : 79.8
Sahiwal : 132.0
Vorderwald : 60.8
Ayrshire : 63.0
Jersey : 128.1
Randall : 57.0
Alderney : 27.0
Carora : 92.4
Gloucester : 112.0