python3基础——读取和写入csv文件

读取csv文件

一、创建一个csv文件

['city', 'password', 'day']

['1', '1', '1']
['2', '1', '1']
['3', '1', '1']
['4', '1', '1']
['5', '1', '1']

二、读取csv文件

import csv

#打开一个csv文件，模式为读取
csvfile = open('/Users/yanghui/Study/python/example.csv','r')
#定义一个变量，进行读取
readCSV = csv.reader(csvfile)
print(readCSV)

#分行打印

for row in readCSV:

print(row)

#读取第一行第二个元素

readCSV = csv.reader(csvfile)
rows = [row for row in readCSV]

print(rows[0][1])

#获取第一行第二个元素

readCSV = csv.reader(csvfile)
for i,rows in enumerate(readCSV):
if i == 0:
row = rows

print(rows[1])

#每列输出打印

readCSV = csv.reader(csvfile)
list1 = []
list2 = []
list3 = []
for row in readCSV:
list1.append(row[0])
list2.append(row[1])
list3.append(row[2])
print(list1)
print(list2)
print(list3)

1 import csv
2 #打开文件，用with打开可以不用去特意关闭file了，python3不支持file()打开文件，只能用open()
3 with open("XXX.csv","r",encoding="utf-8") as csvfile:
4      #读取csv文件，返回的是迭代类型
5      read = csv.reader(csvfile)
6      for i in read:
7           print(i)

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写入csv文件

import csv
#打开一个csv文件，模式为写，如果没有该文件，则创建一个
with open('/Users/yanghui/Study/python/test.csv','a') as csvfile:
#定义一个写变量
writeCSV = csv.writer(csvfile)
writeCSV.writerow(['index','yanghui','18'])