如何使用operator.itemgetter（）對csv文件進行排序

Question

我在csv文件中有一組值。這些值如下所示。我希望這些值按層列進行排序，在下面的示例中，它的值爲7208和7209。否則，我希望csv文件完全按照原樣。我的代碼似乎沒有正確排序。

這裏的CSV文件：

l_d,l_t,utc,SI,UTC,La,Lon,H,layer,N,Pr,EId,Pype,BS,Vo,Te,Chs,PT,Pass 
01-08,11:00:19,03:00:19,0x037,01-08_02:58:03,None,None,None,7208,None,None,None,None,87,15.4,None,None,None,MENT 
01-08,11:00:19,03:00:19,0x037,01-08_02:58:03,None,None,None,7209,None,None,None,None,87,15.4,None,None,None,MENT 

這裏是我當前的代碼：

import sys 
import csv 
import operator 

reader = csv.reader(open("M_B.csv"), delimiter=",") 

sortedlist = sorted(reader, key=operator.itemgetter(9), reverse=True) 

print(sortedlist) 

with open("M_B_Sorted.csv", "wb") as f: 
    writer = csv.writer(f) 
    writer.writerows(sortedlist) 

Answer 1

首先，該指數是錯誤的。它應該是8。

而你需要將字符串轉換爲int;不能與itemgetter唯一目的：

sortedlist = sorted(reader, key=lambda row: int(row[8]), reverse=True) 

---

除此之外，你需要排除頭。

import csv 

with open("M_B.csv") as fin, open("M_B_Sorted.csv", "wb") as f: 
    reader = csv.reader(fin, delimiter=",") 
    writer = csv.writer(f) 
    header = next(reader) # <--- Pop header out 
    writer.writerow(header) # <--- Write header 
    sortedlist = sorted(reader, key=lambda row: int(row[8]), reverse=True) 
    writer.writerows(sortedlist) 

你想