csv的使用(二)

csv的追加写入

import csv

with open('data.csv', 'a') as csvfile:
    fieldnames = ['id', 'name', 'age']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
    writer.writerow({'id': '10004', 'name': 'Durant', 'age': 22})

指定编码格式

• 尝试写入中文的时候，没有使用encoding='utf-8'，在文件中输出的是乱码，所以存在中文就要将编码格式添加上去

import csv

with open('data.csv', 'a', encoding='utf-8') as csvfile:
    fieldnames = ['id', 'name', 'age']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
    writer.writerow({'id': '10005', 'name': 'waws520', 'age': 22})

csv库读取csv文件

import csv

with open('data.csv', 'r', encoding='utf-8') as csvfile:
    reader = csv.reader(csvfile)
    for row in reader:
        print(row)

"""
['id', 'name', 'age']
['10001', 'Mike', '20']
['10002', 'Bob', '22']
['10003', 'Jordan', '21']
['10004', 'Durant', '22']
['10005', 'waws520', '22']
"""

pandas读取csv文件

import pandas  as pd

df = pd.read_csv('data.csv')
print(df)

"""
      id    name  age
0  10001    Mike   20
1  10002     Bob   22
2  10003  Jordan   21
3  10004  Durant   22
4  10005  waws520   22
"""