python - 在 python 中挑选特定模式的字符串的最佳方法是什么？

Question

这是一个字符串列表。

'"5" is a magic number.'
'"6" is a magic number.'
'"7" is a magic number.'
'This line is extra...'
'This line is extra...'
'"8" is a magic number.'

在python中挑选出像“**是一个神奇的数字”这样的最有效方法是什么？

Answer 1

使用列表推导：

mylist = ['"5" is a magic number.', ..., '"8" is a magic number.']
print [i for i in mylist if "is a magic number" in i]

印刷：

['"5" is a magic number.', '"6" is a magic number.', '"7" is a magic number.', '"8" is a magic number.']

使用 re.findall 的正则表达式解决方案：

import re
mylist = ['"5" is a magic number.',
'"6" is a magic number.',
'"7" is a magic number.',
'This line is extra...',
'This line is extra...',
'"8" is a magic number.']
print re.findall(r'"\d+" is a magic number', ' '.join(mylist))

Answer 2

假设您有一个未排序的字符串块，正如您所描述的：

strs='''\
"17" is a magic number.
"6" is a magic number.
"5" is a magic number.
This line is extra...
This line is extra...
"8" is a magic number.'''

现在你想解析和排序字符串中的数字：

import re
out=sorted([s for s in strs.splitlines() if s.endswith('is a magic number.')],
        key=lambda r: int(re.match(r"[\D]*(\d+)",r).group(1)))      

print '\n'.join(out) 

印刷：

"5" is a magic number.
"6" is a magic number.
"8" is a magic number.
"17" is a magic number.

Answer 3

像这样的东西？

my_strings = ['"5" is a magic number.',
'"6" is a magic number.',
'"7" is a magic number.',
'This line is extra...',
'This line is extra...',
'"8" is a magic number.']

print filter(lambda elem: 'magic number' in elem, my_strings)

或使用正则表达式：

import re
p = re.compile("'[0-9]+' is a magic number", re.IGNORECASE)
print filter(lambda elem: bool(p.match(elem)), my_strings)
# if it doesn't match, it returns None which is False