如何按命名列 python、csv 的字母顺序对文件进行排序

Question

我有三个 csv 文件，每个文件包含三个命名列，'Genus'、'Species' 和 'Source'。我将文件合并到一个新文档中，现在我需要按字母顺序排列列，首先按属，然后按物种。我想我可以通过首先按字母顺序排列物种，然后是属，然后它们应该以正确的顺序排列来做到这一点，但我无法在网上找到任何解决如何对命名的字符串列进行排序的内容。我尝试了很多不同的排序方式，但它要么没有改变任何东西，要么用最后一个字符串替换了第一列中的所有字符串。

这是我合并文件的代码：

import csv, sys

with open('Footit_aphid_list_mod.csv', 'r') as inny:
    reader = csv.DictReader(inny)

    with open('Favret_aphid_list_mod.csv', 'r') as inny:
        reader1 = csv.DictReader(inny)

        with open ('output_al_vonDohlen.csv', 'r') as inny:
            reader2 = csv.DictReader(inny)

            with open('aphid_list_complete.csv', 'w') as outty:
                fieldnames = ['Genus', 'Species', 'Source']
                writer = csv.DictWriter(outty, fieldnames = fieldnames)
                writer.writeheader() 

                for record in reader:
                    writer.writerow(record)
                for record in reader1:
                    writer.writerow(record)
                for record in reader2:
                    writer.writerow(record)

                for record in reader:
                    g = record['Genus']
                    g = sorted(g)
                    writer.writerow(record)

inny.closed
outty.closed

Answer 1

如果您的文件不是特别大，则将所有行读入一个列表，排序，然后写回：

#!python2
import csv

rows = []

with open('Footit_aphid_list_mod.csv','rb') as inny:
    reader = csv.DictReader(inny)
    rows.extend(reader)

with open('Favret_aphid_list_mod.csv','rb') as inny:
    reader = csv.DictReader(inny)
    rows.extend(reader)

with open('output_al_vonDohlen.csv','rb') as inny:
    reader = csv.DictReader(inny)
    rows.extend(reader)

rows.sort(key=lambda d: (d['Genus'],d['Species']))

with open('aphid_list_complete.csv','wb') as outty:
    fieldnames = ['Genus','Species','Source']
    writer = csv.DictWriter(outty,fieldnames=fieldnames)
    writer.writeheader()
    writer.writerows(rows)

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