1.查看某文件大小：

os.path.getsize(r'查询的地址')

2.寻找D盘大于500M的文件:

import os
mydir = r'D:\\'
emit_dir ={"System Volume Information","Config.Msi","Program Files","$RECYCLE.BIN"}
def findBig(dir):
    for fname in os.listdir(dir):

        sub_path = os.path.join(dir, fname)

        if os.path.isfile(sub_path):

            size =(os.path.getsize(sub_path))/1024/1024 #换算成MB

            if size>500:
                size =round(size,2)
                print(sub_path,":",size,"MB")
        elif  fname not in emit_dir:
            findBig(sub_path)

if __name__ == "__main__" :
    findBig(mydir)