如何在元组列表中将字符串转换为整数？

Question

My list is like this and following is my code but it does not work.

 templist = [('375ml Bott 24', '6.0', '10.0', '60.0'), ('CHINA WINE', '4.0', '16.0', '64.0')]
 for i in range(len(tempList)):
     tempList[i][1] = int(float(tempList[i][1]))
     tempList[i][2] = int(float(tempList[i][2]))
     tempList[i][3] = int(float(tempList[i][3]))

Answer 1

Using list comprehension with unpacking:

[(s, *map(float, fs)) for s, *fs in templist]

Output:

[('375ml Bott 24', 6.0, 10.0, 60.0), ('CHINA WINE', 4.0, 16.0, 64.0)]

Explanation:

• for s, *fs in ... : for the elements of tuples in templist , take first item ( str ) as s and rest as fs .
• (s, *map(float, fs)) : keep the first item as it is, and convert fs into float then unpacking into a new tuple.

Answer 2

You're trying to change a tuple but you can't since it is immutable. What you can do instead is convert to a list, change the values and convert back to a tuple:

templist = [('375ml Bott 24', '6.0', '10.0', '60.0'), ('CHINA WINE', '4.0', '16.0', '64.0')]

for i,tup in enumerate(templist):
     l = list(tup)
     l[1] = int(float(l[1]))
     l[2] = int(float(l[2]))
     l[3] = int(float(l[3]))
     templist[i] = tuple(l)

print(templist)

Output:

[('375ml Bott 24', 6, 10, 60), ('CHINA WINE', 4, 16, 64)]

You could also use a list comprehension to do the same:

for i,tup in enumerate(templist):
     l = list(tup)
     l[1:] = [int(float(x)) for x in l[1:]]
     templist[i] = tuple(l)

Answer 3

try :

tempList = [['375ml Bott 24', '6.0', '10.0', '60.0'], ['CHINA WINE', '4.0', '16.0', '64.0']]
for i in range(len(tempList)):
    tempList[i][1] = int(float(tempList[i][1]))
    tempList[i][2] = int(float(tempList[i][2]))
    tempList[i][3] = int(float(tempList[i][3]))
print(tempList)

Answer 4

You have a list of tuples. Elements of a list can be changed, it can have different tuple but tuple is immutable. you should have list of lists as mentioned below :

tempList = [['375ml Bott 24', '6.0', '10.0', '60.0'], ['CHINA WINE', '4.0', '16.0', '64.0']]


In this case :
templist = [('375ml Bott 24', '6.0', '10.0', '60.0'), ('CHINA WINE', '4.0', '16.0', '64.0')]

tempList[0] = tempList[1] # can be done because it edit the list which is mutable
tempList[0][1] = tempList[1][1] # can't be done because it edit the tuple which is immutable

Answer 5

Do this: Convert the Tuple inside the List into Lists and convert string to Float.

templist = [('375ml Bott 24', '6.0', '10.0', '60.0'), ('CHINA WINE', '4.0', '16.0', '64.0')]
result =[]
for i in range(len(templist)):
    lis=list(templist[i])
    lis[1] = float(lis[1])
    lis[2] = float(lis[2])
    lis[3] = float(lis[3])
    result.append(lis)
print(result)

Your new list is result

Answer 6

We cant change the type inside a tuple but we can create a new tuple based on the old templist. Try this:

templist = [('375ml Bott 24', '6.0', '10.0', '60.0'), ('CHINA WINE', '4.0', '16.0', '64.0')]
newlist = []
for item in templist:
    z = []
    for i in item:
        try:
            z.append(int(float(i)))
        except:
            z.append(i)
    newlist.append(tuple(z))

print(newlist)

OUTPUT:

[('375ml Bott 24', 6, 10, 60), ('CHINA WINE', 4, 16, 64)]