技術標籤：python

# -*- coding:UTF-8 -*-
# pythonic
"""# 對某個範圍進行迭代
for i in range(6):
    print (i**2)
# 生成器更加高效
for i in xrange(6):
    print (i**2)"""

# 迭代一個集合
colors = ['red','green','blue','yellow']
names = ['raymond', 'rachel', 'matthew']
"""for i in range(len(colors)):
    print colors[i]

for color in colors:
    print color

# 反向迭代
for i in range(len(colors)-1,-1,-1):
    print colors[i]

for color in reversed(colors):
    print color"""
 


"""# 帶下標的迭代
for i in range(len(colors)):
    print("%d ----> %s"%(i,colors[i]))

for i,color in enumerate(colors):
    print ("%d ----> %s"%(i,color))"""

"""# 迭代兩個集合
n = min (len(names),len(colors))
for i in range(n):
    print names[i],'---->',colors[i]
for name,color in zip(names,colors):
    print name,'---->',color
for name,color in izip(names,colors):
    print name, '---->', color"""
 


"""# 以有序的方式進行迭代
for color in sorted (colors):
    print color

for color in sorted(colors,reverse=True):
    print color"""

# 多個出口的判斷for else
"""
def find():
    for ...:
        if ...:
            break
    else:
        return ...(未break時執行)
    
    return ...
"""
 


# 對dict的key進行迭代,需要修改用第二種
d = {'matthew': 'blue', 'rachel': 'green', 'raymond': 'red'}
"""for k in d:
    print k

for k in d.keys():
    if k.startswith('r'):
        del d[k]"""

"""# 迭代字典
for k in d:
    print k, '--->', d[k]
for k,v in  d.items():
    print k, '--->', v
# 返回迭代器
for k, v in d.iteritems():
    print k, '--->', v"""

"""# 對序列進行解包
p = 'Raymond', 'Hettinger', 0x30, '[email protected]'
# A common approach / habit from other languages
fname = p[0]
lname = p[1]
age = p[2]
email = p[3]
print  fname,lname,age,email
fname,lname,age,email = p
print  fname,lname,age,email"""

# 迭代器
# 生成器
"""def gensquares(N):
    for i in range(N):
        yield i ** 2

for item in gensquares(5):
    print item,

def gensquares(N):
    res = []
    for i in range(N):
        res.append(i*i)
    return res

for item in gensquares(5):
    print item,"""
# 裝飾器

"""def decoratorNoparam(func):
    print("this is decoratorNoparam")
    def new(*args,**kwargs):
        func()
        print('new')
        return func(*args,**kwargs)
    print('decoratorNoparam')
    return new

def func():
    print("this is func function")

func1 = decoratorNoparam(func)
func1()"""

"""
this is decoratorNoparam
decoratorNoparam
this is func function
new
this is func function
"""

"""
@decoratorNoparam
def func():
    print("this is func function")
func()

this is decoratorNoparam
decoratorNoparam
this is func function
new
this is func function
"""


# 上下文管理器,自動釋放描述符
"""with context_expr as context_tmp:
    # 函式體"""

"""f = open("D:\codes\hello.txt","r")
print(f.read())
print "是否已關閉 : ", f.closed
f.close()
print "是否已關閉 : ", f.closed"""

"""
with open("D:\codes\hello.txt","r") as fp:
    print "是否已關閉 : ", fp.closed
print "是否已關閉 : ", fp.closed
"""