Python CSV 编写器 [英] Python CSV writer

问题描述

我有一个看起来像这样的 csv:

I have a csv that looks like this:

HA-MASTER,CategoryID
38231-S04-A00,14
39790-S10-A03,14
38231-S04-A00,15
39790-S10-A03,15
38231-S04-A00,16
39790-S10-A03,16
38231-S04-A00,17
39790-S10-A03,17
38231-S04-A00,18
39790-S10-A03,18
38231-S04-A00,19
39795-ST7-000,75
57019-SN7-000,75
38251-SV4-911,75
57119-SN7-003,75
57017-SV4-A02,75
39795-ST7-000,76
57019-SN7-000,76
38251-SV4-911,76
57119-SN7-003,76
57017-SV4-A02,76

我想要做的是重新格式化这些数据，以便每个 categoryID 只有一行，例如:

What I would like to do is reformat this data so that there is only one line for each categoryID for example:

14,38231-S04-A00,39790-S10-A03
76,39795-ST7-000,57019-SN7-000,38251-SV4-911,57119-SN7-003,57017-SV4-A02

我还没有在 excel 中找到可以以编程方式完成此任务的方法.我有超过 100,000 行.有没有办法使用 python CSV Read and Write 来做这样的事情?

I have not found a way in excel that I can accomplish this programatically. I have over 100,000 lines. Is there a way using python CSV Read and Write to do something like this?

推荐答案

有办法:

import csv

def addRowToDict(row):
    global myDict
    key=row[1]
    if key in myDict.keys():
        #append values if entry already exists
        myDict[key].append(row[0])
    else:
        #create entry
        myDict[key]=[row[1],row[0]]


global myDict
myDict=dict()
inFile='C:/Users/xxx/Desktop/pythons/test.csv'
outFile='C:/Users/xxx/Desktop/pythons/testOut.csv'

with open(inFile, 'r') as f:
    reader = csv.reader(f)
    ignore=True
    for row in reader:
        if ignore:
            #ignore first row
            ignore=False
        else:
            #add entry to dict
            addRowToDict(row)


with open(outFile,'w') as f:
    writer = csv.writer(f)
    #write everything to file
    writer.writerows(myDict.itervalues())

只需编辑 inFile 和 outFile

Just edit inFile and outFile

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