如何使用python轻松过滤csv？

Question

假设我有以下CSV文件：

User ID   Name        Application  

001       Ajohns      ABI
002       Fjerry      Central
900       Xknight     RFC
300       JollK       QDI
078       Demik       Central

是否有一些简单的方法（将其导入某些数据结构）？和/或能够在python中轻松执行以下操作：

1) Get all user IDs with Application=Central
2) Get the row where name="FJerry" then extract say the "userid" value from
3) Give me the filtered rows for those with "Application=Central" so I can write out to CSV
4) Give me all the rows where Name="Ajohn", and Application="ABI" such that I could easy do a len() to count them up?

是否有一些python库或者最简单的方法是什么？

Answer 1

使用DictReader琐碎。您需要传递excel-tab作为方言，因为您的字段是制表符分隔的。

rows是一个词典列表。

>>> with open(r'd:\file.csv','rb') as f:
...     reader = csv.DictReader(f,dialect='excel-tab')
...     rows = list(reader)
...
>>> [x['User ID'] for x in rows if x['Application'] == 'Central']
['002', '078']