如何更改 Python 列表中每个字符串的第 n 个字符

Question

Let's say I have the following list of strings:

list = ['ABC.010120.01', 'ABC.010220.02', 'ABC.010220.03']

I want to change the 11th character of each string, meaning the 2nd '.', to a '-'. I've tried:

list = [n[:10] + '-' + n[11:] for n in list]

However this gives me the error:

TypeError: 'float' object is not subscriptable

Answer 1

The problem is that you have a float somewhere in your list. You could use a for loop using enumerate and str to solve it:

lst = ['ABC.010120.01', 'ABC.010220.02', 'ABC.010220.03']
for index, item in enumerate(lst):
    item = str(item)
    lst[index] = item[0:10] + "-" + item[11:]

Or, as a list comprehension:

new_lst = [item[0:10] + "-" + item[11:]
           for x in lst
           for item in [str(x)]]

Also, avoid calling your variables like builtin-objects ( list , dict and the like).

Answer 2

I just tried it on Jupyter localhost as, (it's working):

1

Answer 3

>>> a = ['ABC.010120.01', 'ABC.010220.02', 'ABC.010220.03']
>>> a = [n[:10] + '-' + n[11:] for n in a]
>>> a
['ABC.010120-01', 'ABC.010220-02', 'ABC.010220-03']

Note that list , as str , set and some others are word reserved for python3.

What you're doing it's like change the base of an int , for example.

Answer 4

The issue is that there are nan float values in the list. I found that following this solution linked here worked to remove the nan's from my list as so:

lst = ['ABC.010120.01', 'ABC.010220.02', 'ABC.010220.03', nan]
lst = [x for x in lst if x == x]

Executing that beforehand allows this line to function without error:

lst = [n[:10] + '-' + n[11:] for n in last]