python批量转换图片格式：JPEG到jpg

import osimport stringdirName = r"C:\dateset\ImageNet\data\ImageNet\ILSVRC_bbox_train_v2\Beer\img\\" #最后要加双斜杠，不然会报错li=os.listdir(dirName)for filename in li:newname = filenamenewname = newname.split(".")if newname[-1]=="JPEG":newname[-1]="jpg"newname = str.join(".",newname) #这里要用str.joinfilename = dirName+filenamenewname = dirName+newnameos.rename(filename,newname)print(newname,"updated successfully")