import os

class ScanFile(object):
    def __init__(self,directory,prefix=None,postfix=None):
        self.directory=directory
        self.prefix=prefix
        self.postfix=postfix

    def scan_files(self):
        files_list=[]

        for dirpath,dirnames,filenames in os.walk(self.directory):
            '''
            dirpath is a string, the path to the directory.
            dirnames is a list of the names of the subdirectories in dirpath (excluding '.' and '..').
            filenames is a list of the names of the non-directory files in dirpath.
            '''
            for special_file in filenames:
                if self.postfix:
                    special_file.endswith(self.postfix)
                    files_list.append(os.path.join(dirpath,special_file))
                elif self.prefix:
                    special_file.startswith(self.prefix)
                    files_list.append(os.path.join(dirpath,special_file))
                else:
                    files_list.append(os.path.join(dirpath,special_file))

        return files_list

    def scan_subdir(self):
        subdir_list=[]
        for dirpath,dirnames,files in os.walk(self.directory):
            subdir_list.append(dirpath)
        return subdir_list

if __name__=="__main__":
    dir=r'C:\videos'
    scan=ScanFile(dir)
    subdirs=scan.scan_subdir()
    files=scan.scan_files()