统计文件夹下文件数量（包括子文件夹下的文件）

方法一：迭代

import os
def count_file(path):
    count = 0
    for dir in os.listdir(path):
        if os.path.isfile(os.path.join(path, dir)):
            count += 1
        else:
            count += count_file(os.path.join(path, dir))
    return count

方法二：os.walk()

import os
def count_file(path):
    for dir in os.listdir(path):
        count = 0
        for root, dirs, files in os.walk(os.path.join(path, dir)):
            count += len(files)
    return(count)