1 name = "math"
2 if name == "no":
3     print(88)
4 elif name == "lin":
5     print(77)
6 elif name == "math":
7     print("66")
8 else:
9     print("55")

1 x = [1, 2, 3, 4]
2 while x:
3       if x[0] == 3:
4             print(x[0])
5             break
6       x = x[1:]
7 else:
8       print("not found")

 1 for x in [1, 2, 3, 4]: #遍历列表
 2       print(x)
 3
 4
 5 for s in "python":      #遍历字符串
 6       print(s)
 7
 8
 9
10 T = [(1, 2), (3, 4), (5, 6)]
11 for (a, b) in T:        #遍历元组序列
12       print(a, b)

1
2
3
4
p
y
t
h
o
n
1 2
3 4
5 6

 1 a = list(range(5))
 2
 3 b = list(range(2, 5))
 4
 5 c = list(range(0, 10, 2))
 6
 7
 8 print(a)    #[0, 1, 2, 3, 4]
 9 print(b)    #[2, 3, 4]
10 print(c)    #[0, 2, 4, 6, 8]

1 S = "abcdefghijk"
2
3 a = list(range(0, len(S), 2))
4
5 print(a)    #[0, 2, 4, 6, 8, 10]
6
7 for i in a:
8       print(S[i], end=" ")        #a c e g i k 

 1 #  zip会取一个或者多个序列为参数，然后返回元组的列表，将这些序列中的并排的元素配成对
 2
 3 L1 = [1, 2, 3, 4]
 4 L2 = [5, 6, 7, 8]
 5
 6
 7 a = list(zip(L1, L2))
 8 print(a)    #[(1, 5), (2, 6), (3, 7), (4, 8)]
 9
10 for (x, y) in zip(L1, L2):
11       print(x, y, "--->", x+y)

1 #  在python2中内置map函数，用类似的方法配对起来，但是如果参数长度不同，则会为较短的序列用None补齐
2
3 S1 = "abc"
4 S2 = "xyz123"
5
6 map(None, S1, S2)
7 # [('a', 'x'), ('b', 'y'), ('c', 'z'), (None, '1'), (None, '2'), (None, '3')]

1 #  在python3中 map(f, list):把list上面的元素依次作用于f上，并返回一个新的list
2
3 a = list(map(ord, "spam"))
4 print(a)    #[115, 112, 97, 109]

 1 #  enumerate:同时产生偏移量和元素
 2
 3 S = "spam"
 4 for (x, y) in enumerate(S):
 5       print(x,"--->", y)
 6 '''
 7 输出：
 8       0 ---> s
 9       1 ---> p
10       2 ---> a
11       3 ---> m
12 '''