Python正则表达式模式

Question

I am renaming all of the files in a directory, and using a regex pattern to check if any of the files have a the appropriate file-name structure (I double checked the pattern on www.rubular.com, and it seemed to be correct). If so, it skips renaming he file. The following code renames the file regardless if it has the appropriate file-name structure .... I'm not seeing why it does not skip over the file. Any help in determining why the regex pattern is not working will be appreciated:

# Appropriate file name: P.002-night.jpg; File name to rename: bird.jpg


import os, os.path
import re


def displaymatch(match):
    if match is None:
        return None
    return '<Match: %r, groups=%r>' % (match.group(), match.groups())

sampledir = "c:\\Users\\Name\\Desktop\\New folder"
os.chdir(sampledir)
FileList = os.listdir(os.getcwd())


num = 000

pattern = r"\w.\d{3}\-\w+.(jpg|Jpg|JPG)"


for filename in FileList:
    if displaymatch(re.match(pattern, filename)) != None:
        pass
    else:
        os.rename(filename, "P." + str("{0:0=3d}".format(num)) + "-" + filename)
        num+= 1

Answer 1

pattern = r"\w.\d{3}\-\w+.(jpg|Jpg|JPG)"


for filename in FileList:
    if displaymatch(re.match(pattern, filename)) is None:
        os.rename(filename, "P." + str("{0:0=3d}".format(num)) + "-" + filename)
        num+= 1