正则表达式截取字符串

import re
string = "机器学习359.67.pdf机器学习111.67.txt"

a = re.findall("D*(.*?).[a-z*]",string)
print(a)

b = re.findall("D*(.*?).D+",string)
print(b)

c = re.findall("(.*?.pdf|.*?.txt)",string)
print(c)

结果：
[‘359.67’, ‘111.67’]
[‘359.67’, ‘111.67’]
[‘机器学习359.67.pdf’, ‘机器学习111.67.txt’]