为什么我的python正则表达式锚不能在多行字符串上正常工作?

AS @CertainPerformance 说,用 re.M 结束时的标志 findall :

print(re.findall(my_regex,my_string,re.M))

演示:

>>> import re
>>> my_regex = r'^Credits$'
>>> my_string = "based upon extrinsic circumstances, as discussed in Serrano v. Priest, 20 Cal.3d 25, 49.\n\nCredits\n(Added by Stats.1977, c. 1197, p. 3979,  1. Amended by Stats.1993, c. 645 (S.B.764),  2.)"
>>> print(re.findall(my_regex,my_string,re.M))
['Credits']

或与一起使用 r'(?m)^Credits$' :

>>> import re
>>> my_regex = r'(?m)^Credits$'
>>> my_string = "based upon extrinsic circumstances, as discussed in Serrano v. Priest, 20 Cal.3d 25, 49.\n\nCredits\n(Added by Stats.1977, c. 1197, p. 3979,  1. Amended by Stats.1993, c. 645 (S.B.764),  2.)"
>>> print(re.findall(my_regex,my_string,re.M))
['Credits']