python获取指定路径下的所有文件名

#/usr/bin/python3
#-*- coding=utf-8 -*-

import os

file_dict=[]
def get_file(file_path):
    for dirpath,dirname,filenames in os.walk(file_path):
        for i in range(0,len(filenames)):
            filename = os.path.join(dirpath,filenames[i])
            file_dict.append(filename)

def save_txt(txt_path):
    with open(txt_path,'w',encoding='utf-8') as f:
        for i in range(0,len(file_dict)):
            f.write(file_dict[i])
            f.write('\n')

if __name__ == "__main__":
    path='file_path'
    txt_pat = 'outpu_txt'
    get_file(path)
    save_txt(txt_pat)
    print(len(file_dict))