8 字典的应用

 1 1）应该习惯用此种方法
 2 
 3 li = [11,22,33,44,55,77,88,99,90]
 4 result = {}
 5 for row in li:
 6     if row > 66:
 7         if ‘k1‘not in result:
 8             result[‘k1‘] = []
 9         result[‘k1‘].append(row)
10     else:
11         if ‘k2‘ not in result:
12             result[‘k2‘] = []
13         result[‘k2‘].append(row)
14 print(result)
15 
16 
17 2）可以用此法达到同样效果
18 
19 li = [11,22,33,44,55,77,88,99,90]
20 
21 result = {}
22 
23 for row in li:
24     result.setdefault(‘k1‘,[])
25     result.setdefault(‘k2‘,[])
26     if row > 66 :
27         result[‘k1‘].append(row)
28     else:
29         result[‘k2‘].append(row)
30 print(result)