Defaultdict追加招

Question

我有哪裏元素存儲在兩個列如下所示的文本文件：

a 1,a 3,a 4,b 1,b 2,b 3,b 4,c 1,c 2.... etc 

該文件包含兩列，一個是關鍵a，b，c等，另一種是元素1,2,3,4等

我用defaultdict存儲這些項目並附加它們。 默認字典的項目有：

defaultdict(<type 'list'>, `{'a': ['0', '1', '2', '3', '4'], 'c': ['1', '2'], 'b': ['1', '2', '3', '4']}`) 

我用下面的命令：

from collections import defaultdict 
positions = defaultdict(list) 

with open('test.txt') as f: 
    for line in f: 
     sob = line.split() 
     key=sob[0] 
     ele=sob[1] 
     positions[key].append(ele) 
    print positions 

Answer 1

insted的defaultdict，你可以使用OrderedDict

from collections import OrderedDict 
positions = OrderedDict() 
with open('test.txt') as f: 
    for line in f: 
     key, ele = line.strip().split() 
     positions[key] = positions.get(key, []) + [ele] 
print positions