python列表、字典與csv

在平常數據分析時最常打交道的是csv文件和list,dict類型。涉及到的主要需求有：

1. 將一個二重列表[[],[]]寫入到csv文件中
2. 從文本文件中讀取返回爲列表
3. 將一字典寫入到csv文件中
4. 從csv文件中讀取一個字典
5. 從csv文件中讀取一個計數字典

實現以下：

# 功能：將一個二重列表寫入到csv文件中
# 輸入：文件名稱，數據列表
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：從文本文件中讀取返回爲列表的形式
# 輸入：文件名稱，分隔符（默認,）
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：將一字典寫入到csv文件中
# 輸入：文件名稱，數據字典
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：從csv文件中讀取一個字典
# 輸入：文件名稱，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：從csv文件中讀取一個計數字典
# 輸入：文件名稱，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