Question

我正在编写一个代码，该代码应该包含文件名并创建一个初始列表。然后，我试图总结列表中的每个项目。到目前为止我写的代码看起来像这样......

filename = input('Enter filename: ')
    Lists = []
    for line in open(filename):
        line = line.strip().split()
        Lists = line
    print(Lists)
    total = 0
    for i in Lists:
        total = sum(int(Lists[i]))
    print(total)

我接受一个文件名并将line =中的所有对象设置为List。然后，我创建一个变量total，它应该打印出列表中每个项目的总和。例如，如果List = [1,2,3]则总数将为6.但是，是否可以将整数对象附加到列表中？我收到的错误是......

File "/Users/sps329/Desktop/testss copy 2.py", line 10, in main
    total = sum(int(Lists[i]))
TypeError: list indices must be integers, not str

这样的东西也不起作用，因为List中的项目是字符串而不是数字。我是否必须实现函数isdigit，即使我知道输入文件将始终是整数？...

total = sum(i)

Answer 1

而不是
```
Lists = line
```
你需要
```
Lists.append(line)
```

你可以得到这样的总和

total = sum(sum(map(int, item)) for item in Lists)

如果您不想创建列表列表，可以使用extend函数
```
Lists.extend(line)
...
total = sum(map(int, Lists))
```

Answer 2

# creates a list of the lines in the file and closes the file
with open(filename) as f:
    Lists = f.readlines()

# just in case, perhaps not necessary
Lists = [i.strip() for i in Lists]

# convert all elements of Lists to ints
int_list = [int(i) for i in Lists]

# sum elements of Lists
total = sum(int_list)

Answer 3

print sum([float(x.strip()) for x in open(filename)])

总结一个列表的对象

3 个答案: