相关推导式-Python
列表、’字典等推导式
1 #利用zip()函数同时给多个变量赋值
2 a = [1,2,3,4,5]
3 b = [4,5,6,7,8]
4 c = [9,2,3,4,0]
5 l = [[1,2],[3,4]]
6 for x,y,z in zip(a,b,c):
7 print(x,y,z)
8
9 #利用推导式来找符合条件的两个列表中的元素
10 d = [i for i in a if i not in b]
11 print(d)
12 #if not为假的时候执行,与if相反
13 e = [j+1 if not j%2 else j-1 for j in a]
14 print(e)
15 #两个for的推导式
16 f = [(i,j) for i in a if i%2 for j in b if j>5]
17 print(f)
18 g = [x for y in l for x in y]
19 print(g)
20 #遍历字典
21 list1 = [('HW','华为'),('ZTE','中兴'),('MI','小米'),('CISCO','思科')]
22 dict1 = {key:value for key,value in list1}
23 print(dict1)
24 #将字典键和值对调
25 dict2 = {'k1':'10','k2':'20','k3':'30'}
26 new_dict2 = {value:key for key,value in dict2.items()}
27 print(new_dict2)
#变量赋值推导式
>>> a=1
>>> t=3
>>> d = a+1 if t<4 else a-1
>>> d
2
>>> d = a+1 if t>4 else a-1
>>> d
0
#自加推导式
x += 2 if tag else +1
