CSV file: Comma-Separated Values, Chinese name, comma-separated value or character-separated value, its file store table data in the form of plain text. The file is a sequence of characters, which can consist of any number of records, separated by some kind of newline character. Each record is composed of fields, and the separator between fields is other characters or strings. All records have exactly the same sequence of fields, which is equivalent to the plain text form of a structured table.
CSV files can be opened with text files, Excel or similar and text files.

Write to CSV

Write data to a CSV file in Python, an example is as follows:

import csv #Need to import library
withopen('data.csv','w')as fp:
 writer = csv.writer(fp)#Pass in the file handle first
 writer.writerow(['id','name','age'])#Then write
 writer.writerow(['10001','mike','20'])#Write by line
 writer.writerow(['10002','Bob','22'])
 writer.writerow(['10003','Jordan','21'])

Modify the separator between columns and pass in the delimiter parameter:

import csv #Need to import library
withopen('data.csv','w')as fp:
 writer = csv.writer(fp,delimiter ='*')#delimiter can only be a one-byte character
 writer.writerow(['id','name','age'])#Then write
 writer.writerow(['10001','mike','20'])#Write by line
 writer.writerow(['10002','Bob','22'])
 writer.writerow(['10003','Jordan','21'])

Write the title first, and write the data:
Note: The data is a list, and use the writerows() method

Write to csv as a dictionary

import csv
withopen('data.csv','w')as fp:
 fieldnames =['id','name','age']  #First define the key in the dictionary
 # Use DictWriter() method to add a fieldnames
 writer = csv.DictWriter(fp,fieldnames  = fieldnames,delimiter ='+') 
 writer.writeheader()#Write key first
 # Write in the dictionary
 writer.writerow({'id':'10001','name':'mike','age':'20'})
 writer.writerow({'id':'10002','name':'Bob','age':'22'})
 writer.writerow({'id':'10003','name':'Jordan','age':'21'})

Read CSV

There are two ways to read CSV files:

The first

import csv
withopen('data.csv','r',encoding ='utf8')as fp:
 reader = csv.reader(fp)for row in reader:print(row)

The second

import pandas as pd #Need to import pandas library
df = pd.read_csv('data.csv')print(df)

Python data format-CSV

Write to CSV

Read CSV