0403CSV

CSV(Comma-Separated Values)文件存储(p134)

存储

1.列名和数据行分开写入

import csv

with open('data.csv', 'w') as file:
    writer = csv.writer(file) #默认以逗号分隔，修改分隔符 delimiter=' '
    #①.单行写入
    writer.writerow(['id', 'name', 'age'])
    writer.writerow(['10001', 'Mike', 20])

    #②.多行写入
    #writer.writerows([['10001', 'Mike', 20], ['10002', 'Bob', 22]])

2.结构化（字典）写入

import csv

with open('data.csv', 'w') as file:
  writer = csv.DictWriter(file, fieldnames = ['id', 'name', 'age'] )
  writer.writeheader()
  writer.writerow({'id': '10001', 'name': 'Mike', 'age': 20})
  writer.writerow({'id': '10002', 'name': 'Bob', 'age': 22})

3.pandas库

#pip3 install pandas
data = [{'id': '10001', 'name': 'Mike', 'age': 20},
    {'id': '10002', 'name': 'Bob', 'age': 22},
    {'id': '10003', 'name': 'Jordan', 'age': 21},]
df = pd.DataFrame(data)
df.to_csv('data.csv', index=False)

读取

1.csv库读取

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

2.pandas库读取

import pandas as pd
df = pd.read_csv('data.csv')
#①.迭代
for i, row in df.iterrows():
    print(row.tolist())

##②.所有数据转换成list
#data = df.values.tolist()