文章目录

• ​​一、准备一个csv文件（test.csv）​​
• ​​二、读取csv文件​​

• ​​输出整个文件的数据​​
• ​​输出具体信息​​
• ​​输出所有的年龄​​
• ​​修改tom的年龄为20​​
• ​​增加一列信息​​

• ​​三、写入csv文件​​
• ​​四、完整代码​​
• ​​五、参考文章​​

一、准备一个csv文件（test.csv）

二、读取csv文件

输出整个文件的数据

import csv
with open('test.csv', 'r', encoding='utf-8') as f:
    data = [row for row in csv.DictReader(f)]
    print(data)

打印出来的值是一个列表里面嵌套了字典

输出具体信息

print(data[0]["age"]) #输出lili的年龄，0代表第一行

输出所有的年龄

with open('test.csv', 'r', encoding='utf-8') as f:
    data = [row for row in csv.DictReader(f)]
    for i in range(len(data)):
        print(data[i]["age"])

修改tom的年龄为20

data[1]["age"] = 20
print(data)

增加一列信息

data[0]["phone"] = "123456"
data[1]["phone"] = "456789"
print(data)

三、写入csv文件

header = data[0].keys()     # 获取表头
with open('test_output.csv', 'w', encoding='utf-8', newline='') as f:
    writer = csv.DictWriter(f, fieldnames=header)
    writer.writeheader()    # 写入表头
    writer.writerows(data)  # 写入数据

四、完整代码

#!/usr/bin/env python
# -*- coding:utf-8 -*-

import csv

with open('test.csv', 'r', encoding='utf-8') as f:
    data = [row for row in csv.DictReader(f)]
    data[1]["age"] = 20
    data[0]["phone"] = "123456"
    data[1]["phone"] = "456789"

header = data[0].keys()     # 获取表头
with open('test_output.csv', 'w', encoding='utf-8', newline='') as f:
    writer = csv.DictWriter(f, fieldnames=header)
    writer.writeheader()    # 写入表头
    writer.writerows(data)  # 写入数据

五、参考文章

​​Python 修改CSV文件实例详解​​