import os
def file_name(file_dir):
    a=list(os.walk(file_dir))[0][2]
    for files in a:
        if '.csv' not in files:
            list(a).remove(files)
      
        return a
        
        
dalu='C:\\Users\\sse\\Downloads\\v42\\v4'
ttt=file_name(dalu)



for target in ttt:



    fd = open(dalu+'\\'+target, 'r',encoding='utf-8')    
    t=fd.readlines()
    with open(dalu+'\\'+target, 'w', encoding="gbk") as dst:    
        for line in t:

            dst.write(line)
    fd.close()
    dst.close()