csv文件的操作

#csv(逗号分隔符)，它是一种通用的文件格式，它可以非常轻易的被导入到各Eexcel表格或者数据库当中。csv文件，一行代表一条数据。
import csv
#将列表写入到csv文件当中
rows=[["张三","20"],["李四","25"],["王五","23"],["麻子","26"]]
#使用上下文管理器
# with open("test1.csv","w",encoding="utf-8",newline="") as f:
#     #通过csv模块创建一个用于写入数据的对象writer
#     writer=csv.writer(f)
#     writer.writerow(["姓名","年龄"])
#     for row in rows:
#         writer.writerow(row)
#
# with open("test2.csv","w",encoding="utf-8",newline="") as f:
#     #通过csv模块创建一个用于写入数据的对象writer
#     writer=csv.writer(f)
#     writer.writerow(["姓名","年龄"])
#     writer.writerows(rows)

#对列表的读取
# with open("test1.csv",'r',encoding="utf-8") as f:
#         # 通过csv模块创建一个用于读取数据的对象reader
#         reader=csv.reader(f)
#         print(reader)
#         for row in reader:
#             print(row)


#csv文件对字典的操作
rows1=[{"name":"张三","age":"20","sex":"男"},{"name":"李四","age":"22","sex":"男"},{"name":"王五","age":"23","sex":"男"},{"name":"小红","age":"20","sex":"女"},{"name":"小丽","age":"20","sex":"女"}]

# keys=[key for key in rows1[0]]
# print(keys)
# with open("test3.csv","w",encoding="utf-8",newline="")as f:
#     keys=[key for key in rows1[0]]
#     #创建一个用于写入字典数据的对象
#     #fildnames:是用来设置excel表的表头
#     writer=csv.DictWriter(f,fieldnames=keys)
#     #写入表头内容
#     writer.writeheader()
#     writer.writerows(rows1)
#     # for dict in rows1:
#     #     writer.writerow(dict)

#csv对字典数据的读取
with open("test3.csv","r",encoding="utf-8") as f:
    reader=csv.DictReader(f)
    for row in reader:
        print(row)
        print(type(row))
        print(row["name"],row["age"],row["sex"])