### 1.说明 CSV，全称叫做Comma-Separated Values，即逗号分隔符或字符分隔符 ### 2.写入 通过open\(\)方法写入并创建一个csv文件，调用csv库的writer\(\)方法初始化一个写入对象，传入该语柄，然后调用writerow\(\)方法传入每行的数据即可完成写入 ``` import csv with open('data.csv', 'w',newline='') as csvfile: writer = csv.writer(csvfile) writer.writerow(['id', 'name']) writer.writerow(['10001', '米库']) ``` 注意:如果不带newline=‘’，会发现也能写入结果，但是每行内容之间总是会多出一个空行 如果想修改列与列之间的分隔符可以传入delimiter参数 ``` import csv with open('data.csv', 'w',newline='') as csvfile: writer = csv.writer(csvfile,delimiter='0') writer.writerow(['id', 'name']) writer.writerow(['10001', '米库']) ``` 默认的分隔符逗号\(,\)会被换成delimeter参数设置的分隔符 可以同时传入多行，需要使用witerrows\(\)方法 注意:是writerrows而不是writerow ``` import csv with open('data.csv', 'w',newline='') as csvfile: writer = csv.writer(csvfile) writer.writerow(['id', 'name']) writer.writerows([['10001', '米库'],['10001', '米库'],['10001', '米库']]) ``` 以字典的形式写入csv文件 ``` import csv with open('data.csv', 'w',newline='') as csvfile: # 预先定义字段 fieldnames = ['id','name'] # 初始化一个字典写入对象 writer = csv.DictWriter(csvfile, fieldnames=fieldnames) # 调用writeheader()方法先写入头信息 writer.writeheader() # 调用writerow传入相应字典 writer.writerow({'id':1,"name":"angle"}) ``` 追加csv文本内容 注意这里就不同调用writeheader\(\)方法，不然会将头部信息一并写入 ``` import csv with open('data.csv', 'a',newline='') as csvfile: # 预先定义字段 fieldnames = ['id','name'] # 初始化一个字典写入对象 writer = csv.DictWriter(csvfile, fieldnames=fieldnames) # 调用writerow传入相应字典 writer.writerow({'id':1,"name":"angle"}) ``` 若将中文写入csv文件中，需要指定编码格式 ``` import csv with open('data.csv', 'a',newline=''，encoding='utf-8') as csvfile: # 预先定义字段 fieldnames = ['id','name'] # 初始化一个字典写入对象 writer = csv.DictWriter(csvfile, fieldnames=fieldnames) # 调用writerow传入相应字典 writer.writerow({'id':1,"name":"angle"}) ``` 利用pandas库写入csv文件 注意，字典的键值对中值的类型是列表形式 ``` import pandas as pd data = { 'name':["angle"], "age":[18], } print(data) df = pd.DataFrame(data) # print(df) df.to_csv('csv1.csv') ``` ### 3.读取 ``` import csv with open('data.csv','r',encoding='utf-8') as csvfile: reader = csv.reader(csvfile) for content in reader: print(content) ``` 运行结果: ``` ['id', 'name'] ['1', 'angle'] ['id', 'name'] ['1', 'angle'] ['id', 'name'] ``` 利用pandas中read\_csv\(\)方法将数据从csv中读取出来 ``` import csv with open('data.csv', 'w',newline='',encoding='utf-8') as csvfile: writer = csv.writer(csvfile) writer.writerow(['id', 'name']) writer.writerows([['10001', '米库'],['10001', '米库'],['10001', '米库']]) # 用pandas读取csv文本内容，需要写入csv文本后时指定编码格式utf-8 import pandas as pd print(pd.read_csv('data.csv')) ``` 运行结果: ``` id name 0 10001 米库 1 10001 米库 2 10001 米库 ```