Python的Dictreader排序字段名

Question

我有一個.csv文件與內容（例如）

Attributes,Description,Dial-Up 
4,2,0.2 
3,1,0.4 

使用dictreader：

dictreader = csv.DictReader(open(filename, "rb"), delimiter=',') 
dictdata = {} 
count=0 
for row in dictreader: 
    dictdata[count]=row 
    count=count+1 

而且使用作家在顯示錶或我會得到：

Dial-Up,Attributes,Description 
0.2,4,2 
0.4,3,1 

那麼如何排序字段名？

Answer 1

的DictReader存儲在屬性中的字段（字典鍵）稱爲fieldnames：

fields = dictreader.fieldnames 
print(fields) 
# ['Attributes', 'Description', 'Dial-Up'] 

因此打印的行值順序如下：

print(','.join(fields)) 
for row in dictreader: 
    print(','.join(row[field] for field in fields)) 

產量

Attributes,Description,Dial-Up 
4,2,0.2 
3,1,0.4 

---

或者，使用@JonClements'的想法：

import operator 
fields = dictreader.fieldnames 
getfields = operator.itemgetter(*fields) 
for row in dictreader: 
    print(','.join(getfields(row))) 

使用operator.itemgetter是，這是比使用列表理解更快的動機：

In [70]: %timeit getfields(row) 
10000000 loops, best of 3: 174 ns per loop 

In [71]: %timeit [row[field] for field in fields] 
1000000 loops, best of 3: 272 ns per loop