取出檔名

/User/hank/files/blabla/abc def.pdf -> abc def.pdf

^.+\\\\/([^\\\\/]+)$

夾在兩個東西之間

![[applepie 123]] → applepie 123

• (?<=...) 某東西開頭
• (?=...) 某東西結尾

(?<=!\\\\[\\\\]).+?(?=\\\\]\\\\])'

在 sub 的時候數數

apple.png, banana.png, orange.png → image 1.png, image 2.png, image 3.png

class SubCounter(object):
    def __init__(self, start=1):
        self.count = start - 1
    def __call__(self, match):
        self.count += 1
        return f"image {self.count}{match.group(1)}"
    
re.sub(r"\\\\w*?(.png)", SubCounter(), "apple.png, banana.png, orange.png")