#!/usr/bin/env python3
# _*_ coding:utf-8 _*_

# 高级特性  切片
import os
from collections import Iterable

L = list(range(100))
print(L)
print(L[:10])
print(L[-10:-1])
print(L[:10:2])
print(L[::5])

print('asdgasdasdf23232'[:3])
print(' 我会中文，因为为是中国人 '[1:4])


def trim(s):
    if (s[:1] == ' '):
        return trim(s[1:-1])
    if (s[-2:-1] == ' '):
        return (s[0:-2])
    return s


print(trim(' sdf zas '))

#  迭代
d = {'a': 1, 'b': 2, 'c': 3}

for k, v in d.items():
    print(k, v)
print(isinstance('abc', Iterable))
print(isinstance('[1,2,3]', Iterable))
print(isinstance(12, Iterable))

# 列表生成式 (List Comprehensions)
print(list(range(1, 11)))
# 生成[1x1,2x2,3x3,....,10x10]

L = []
for x in range(1, 11):
    L.append(x * x)
print(L)

print([x * x for x in range(1, 11)])

L1 = [x * x for x in range(1, 11) if x % 2 == 0]
print(L1)

L2 = [m + n for m in 'ABC' for n in '123']
print(L2)

# 列出当前目录中所有的文件和目录名
L3 = [d for d in os.listdir('.')]
print(L3)

L4 = ['Hello', 'World', 'IBM', 'Apple', 12]
L5 = [isinstance(s, str) and s.lower() for s in L4]
print(L4)
print(L5)
d = {'x': 'A', 'y': 'B', 'z': 'C'}
L6 = [x + '=' + y for x, y in d.items()]
print(L6)

# 生成器(genterater)  生成器保存的是算法
g = (x * x for x in range(10))
# print(g)
for n in g:
    print(n)


def fib(max):
    n, a, b = 0, 0, 1
    while n < max:
        # print(b)
        yield b
        a, b = b, a + b
        n = n + 1
    return 'done'


for x in fib(6):
    print(x)


def odd():
    print('step 1')
    yield 1
    print('step 2')
    yield 3
    print('step 3')
    yield 7


o = odd()
next(o)
next(o)

print('*' * 20, '杨辉三角')


def triangles():
    n = 0
    L1 = [1]
    L2 = [1, 1]
    while n < 10:
        if n == 1:
            print(L1)
        if n == 2:
            print(L2)
        else:
            print()
        # L1, L2 = L2, [m + n for m in L1 for n in L2]
        n = n + 1


# triangles()

# n = 10
# results = []
# for t in triangles():
#     print(t)
#     results.append(t)
#     n = n + 1;
#     if n == 10:
#         break

it = iter([1, 2, 3, 4, 5])
while True:
    try:
        x = next(it)
        print(x)
    except StopIteration:
        break