从列表中的元素中删除括号

Question

I am a beginner in python and I have not done regex. I am trying to get rid of '(' and ')' from elements in a list. I tried the following but it does not work.

def trial(st):
    a=st.split()
    ls=[]
    for item in a:
        ls.append(item.replace('(',''))
    return a

>>>trial("(   +(       + 8        7)(    + 2 5     ))")   
['(', '+(', '+', '8', '7)(', '+', '2', '5', '))']

I am trying to get the following:

>>>trial("(   +(       + 8        7)(    + 2 5     ))")   
['+', '+', '8', '7', '+', '2', '5']

Answer 1

为什么不先删除括号？

a = st.replace("("," ").replace(")"," ").split()

Answer 2

Regex is quite usefull here:

>>> import re
>>> s = "(   +(       + 8        7)(    + 2 5     ))"
>>> re.findall("[+0-9]+",s)
['+', '+', '8', '7', '+', '2', '5']

if you dont have studied regex:

>>> [x for x in s if x=='+' or x.isdigit()]
['+', '+', '8', '7', '+', '2', '5']

str.isdigit() will check is the string is digit or not