多维列表排序、文件夹遍历、python列表字典csv读取

• 多维列表排序：先根据第一列排序，然而第二列，然后第三列

import operator

alist=[[],[],[],[]]
alist.sort(key=operator.itemgetter(0,1,2))

• 遍历文件夹下的文件

import os  
path = "D:/Python34/news" #文件夹目录  
files= os.listdir(path) #得到文件夹下的所有文件名称 
for file in files: #遍历文件夹  
     if not os.path.isdir(file): #判断是否是文件夹，不是文件夹才打开  
          f = open(path+"/"+file); #打开文件  

• 读取csv文件写入列表

import csv
with open('A.csv','rb') as csvfile:
    reader = csv.reader(csvfile)
    rows= [row for row in reader]
print rows

得到如：
[[‘No.’, ‘Name’, ‘Age’, ‘Score’],
[‘1’, ‘Apple’, ‘12’, ‘98’],
[‘2’, ‘Ben’, ‘13’, ‘97’],
[‘3’, ‘Celia’, ‘14’, ‘96’],
[‘4’, ‘Dave’, ‘15’, ‘95’]]

• python列表、字典与csv

1、将一个二重列表[[],[]]写入到csv文件中
2、从文本文件中读取返回为列表
3、将一字典写入到csv文件中
4、从csv文件中读取一个字典
5、从csv文件中读取一个计数字典

https://www.cnblogs.com/moye13/p/5291156.html

# 功能：将一个二重列表写入到csv文件中
# 输入：文件名称，数据列表
def createListCSV(fileName="", dataList=[]):
    with open(fileName, "wb") as csvFile:
        csvWriter = csv.writer(csvFile)
        for data in dataList:
            csvWriter.writerow(data)
        csvFile.close

# 功能：从文本文件中读取返回为列表的形式
# 输入：文件名称，分隔符（默认,）
def readListCSV(fileName="", splitsymbol=","):
    dataList = []
    with open(fileName, "r") as csvFile:
        dataLine = csvFile.readline().strip("\n")
        while dataLine != "":
            tmpList = dataLine.split(splitsymbol)
            dataList.append(tmpList)
            dataLine = csvFile.readline().strip("\n")
        csvFile.close()
    return dataList

# 功能：将一字典写入到csv文件中
# 输入：文件名称，数据字典
def createDictCSV(fileName="", dataDict={}):
    with open(fileName, "wb") as csvFile:
        csvWriter = csv.writer(csvFile)
        for k,v in dataDict.iteritems():
            csvWriter.writerow([k,v])
        csvFile.close()

# 功能：从csv文件中读取一个字典
# 输入：文件名称，keyIndex,valueIndex
def readDictCSV(fileName="", keyIndex=0, valueIndex=1):
    dataDict = {}
    with open(fileName, "r") as csvFile:
        dataLine = csvFile.readline().strip("\n")
        while dataLine != "":
            tmpList = dataLine.split(splitsymbol)
            dataDict[tmpList[keyIndex]] = tmpList[valueIndex]
            dataLine = csvFile.readline().strip("\n")
        csvFile.close()
    return dataDict

# 功能：从csv文件中读取一个计数字典
# 输入：文件名称，keyIndex
def readDictCSV(fileName="", keyIndex=0):
    dataDict = {}
    with open(fileName, "r") as csvFile:
        dataLine = csvFile.readline().strip("\n")
        while dataLine != "":
            tmpList = dataLine.split(splitsymbol)
            if dataDict.get(tmpList[keyIndex]) == None:
                dataDict[tmpList[keyIndex]] = 0
            dataDict[tmpList[keyIndex]] = dataDict.get(tmpList[keyIndex]) + 1
            dataLine = csvFile.readline().strip("\n")
        csvFile.close()
    return dataDict