python中CSV文件读写操作是什么

import csv####第一种方式使用csv的reader() writer()#读取test.csv文件，这里指定了字符集编码UTF-8-sigencode = 'UTF-8-sig'with open('test.csv','r',encoding=encode) as csv_file:  #获取csv reader读取对象  #delimiter参数默认值逗号 可不写  csv_reader = csv.reader(csv_file,delimiter=',')  #打开test_copy.csv文件  with open('test_copy.csv','w',encoding=encode) as w_file:    #获取csv writer写入对象    #为了区分效果delimiter分隔符用-    csv_writer = csv.writer(w_file,delimiter='-')    #循环数据，写入每一列到新的文件中    for line in csv_reader:      csv_writer.writerow(line)####第二种方式使用csv的dictionary reader####dictionary writer方法实现####本人更喜欢第二种方式with open('test.csv','r',encoding=encode) as csv_file:  csv_reader = csv.DictReader(csv_file,delimiter=',')  with open('test_csv_copy.csv','w',encoding=encode) as new_file:    #这里定义新的csv字段名字只保留姓名和性别    fieldnames = ['姓名','性别']    csv_writer = csv.DictWriter(new_file,fieldnames=fieldnames,delimiter='\t')    #先把表头写入    csv_writer.writeheader()    for line in csv_reader:    #获取的每一行数据为字典形式        #eg:OrderedDict([('\ufeff姓名', '企鹅'), ('年龄', '23'), ('性别', '女')])        #删除掉年龄      del line['年龄']      csv_writer.writerow(line)