正则表达式re.sub用于python中的字符串格式化

Question

Quite new to regular expressions and am trying to get a grasp on them

string = "regex_learning.test"
subbed = re.sub(r'(.*)_learning(.*), r'\1', string)

What I was hoping for is "regex.test" as an ouput when printing subbed , however I just get "regex"

Could someone explain why I am losing the .test?

Thanks in advance

Answer 1

Use this:

subbed = re.sub(r'(.*)_learning(.*)', r'\1' + r'\2', string)

You can also write it as:

subbed = re.sub(r'(.*)_learning(.*)', "%s%s" % (r'\1', r'\2'), string)