python - 如何从Python IO流中删除最后一个字符

Question

import io
my_list = [{'id': 1, 'updated_at': 20}, {'id': 2, 'updated_at': 10} ]
string_out = io.StringIO()
first_obj = my_list[0]
keys = first_obj.keys()
for i in keys:
    string_out.write(i)
    string_out.write(",")

print(string_out.getvalue())

输出:- id,updated_at,

我想从我的信息流中删除最后一个“,”(逗号)。？

我想删除最后一个字符，该字符可能是我使用命令仅用于示例目的的任何内容。

Answer 1

您可以直接使用 join 和 , 来编写，

>>> import io
>>> my_list = [{'id': 1, 'updated_at': 20}, {'id': 2, 'updated_at': 10} ]
>>> string_out = io.StringIO()
>>> first_obj = my_list[0]
>>> keys = first_obj.keys()
>>> string_out.write(','.join(keys))
13
>>> print(string_out.getvalue())
id,updated_at
>>> 

或者更好，

>>> string_out = io.StringIO()
>>> my_list
[{'id': 1, 'updated_at': 20}, {'id': 2, 'updated_at': 10}]
>>> for idx,d in enumerate(my_list):
...   if idx == 0:
...     string_out.write(','.join(d.keys()) + '\n')
...   string_out.write(','.join(str(x) for x in d.values()) + '\n')
... 
14
5
5
>>> print(string_out.getvalue())
id,updated_at
1,20
2,10