获取字符串中的邮政编号（数字）

Question

如何在@之后和之前找到数字（帖子编号）;;因为字符串中还有其他数字。最后，它产生了 [507, 19, 1]。

例子：

   post507 = "@507::empty in Q1/Q2::can list be empty::yes"
   post19 = "@19::Allowable functions::empty?, first, rest::"
   post1 = "@1::CS116 W2015::Welcome to first post::Thanks!"
   cs116 =   [post507, post1, post19]


   print (search_piazza(cs116, "l")) =>[507,1,19]

Answer 1

(?<=@)\d+

使用lookbehind。查看演示。

https://regex101.com/r/eS7gD7/33#python

import re
p = re.compile(r'(?<=@)\d+', re.IGNORECASE | re.MULTILINE)
test_str = "\"@507empty in Q1/Q2can list be emptyyes\"\n \"@19Allowable functionsempty?, first, rest\"\n \"@1CS116 W2015Welcome to first postThanks!"

re.findall(p, test_str)

iF 输入在list

使用

x=["@507;;empty in Q1/Q2;;can list be empty;;yes",
"@19;;Allowable functions;;empty?, first, rest;;",
"@1;;CS116 W2015;;Welcome to first post;;Thanks!"]
print [re.findall(r"(?<=@)\d+",k) for k in x]

Answer 2

如何在@之后和;;之前的字符串中查找数字（帖子编号）

将re.findall 与 list_comprehension 一起使用。

>>> l = ["@507;;empty in Q1/Q2;;can list be empty;;yes",
    "@19;;Allowable functions;;empty?, first, rest;;",
    "@1;;CS116 W2015;;Welcome to first post;;Thanks!"]
>>> [j for i in l for j in re.findall(r'@(\d+);;', i)]
['507', '19', '1']

最后将得到的数字转换为整数。

>>> [int(j) for i in l for j in re.findall(r'@(\d+);;', i)]
[507, 19, 1]

没有正则表达式。

>>> l = ["@507;;empty in Q1/Q2;;can list be empty;;yes",
    "@19;;Allowable functions;;empty?, first, rest;;",
    "@1;;CS116 W2015;;Welcome to first post;;Thanks!"]
>>> for i in l:
        for j in i.split(';;'):
            for k in j.split('@'):
                if k.isdigit():
                    print(k)


507
19
1

列表理解：

>>> [int(k) for i in l for j in i.split(';;') for k in j.split('@') if k.isdigit()]
[507, 19, 1]