python CSV读写文件

1、读文件

#第一种方法
import csv

f=open("data.csv","r")
reader = csv.reader(f)
a = list(reader)
print(a)
reader.close()

#第二种方法
import csv

f=open("data.csv","r")
reader = csv.reader(f)
for i in reader:
    print(i)
reader.close()

#第三种方法
import csv

with open("data.csv","r") as f:
    read = csv.reader(f)
    for i in read:
        print(i)

#第四种方法
import csv

with open("data.csv","r") as f:
    read = csv.DictReader(f)
    for row in read:
        print(row["name"])

2，写文件

如果准备写入的文件是列表格式

import csv

#表头
headers = ["name","age","sex"]
#准备写入的内容
rows = [
    ["lv",40,"男"],
    ["liying",39,"女"]

]
with open("dd.csv","w",newline="") as f:
    f_csv = csv.writer(f)
    #写入表头
    f_csv.writerow(headers)
    #写入内容
    f_csv.writerows(rows)

如果准备写入的文件是字典格式

import csv

headers = ["name","age","sex"]
#准备写入的内容是字典类型
rows = [
    {"name":"lv","age":40,"sex":"男"},
    {"name":"li","age":36,"sex":"女"},

]
with open("dw.csv","w",newline="") as f:
    f_csv = csv.DictWriter(f,headers)
    f_csv.writeheader()
    f_csv.writerows(rows)