切片，迭代，列表生成式，生成器的代码练习

Author: kangxiaoyu

2017-04-24/diedaiqi/odd_g.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+#这里，最难理解的就是generator和函数的执行流程不一样。
+#函数是顺序执行，遇到return语句或者最后一行函数语句就返回。i
+#而变成generator的函数，在每次调用next()的时候执行，遇到yield语句返回，再次执行时从上次返回的yield语句处继续执行。
+def odd():
+	print 'step 1'
+	yield 1
+	print 'step 2'
+	yield 3
+	print 'step 3'
+	yield 5
+o = odd()
+print o.next()
+print o.next()
+print o.next()

2017-04-24/diedaiqi/triangle.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+#我爱中文
+def fib(max):
+	n,a,b=0,0,1
+	while n < max:
+		yield b
+		a,b=b,a+b
+		n=n+1
+print fib(6)

2017-04-24/filter/filter_empty.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def not_empty(s):
+	return s and s.strip()
+print filter(not_empty,['A','','B',None,'C',''])

2017-04-24/filter/filter_odd.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def is_odd(n):
+	return n%2 == 1
+
+print filter(is_odd,[1,2,4,5,6,9,10,15])

2017-04-24/generator/generator2.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+L=[x*x for x in range(10)]
+print L
+g=(x*x for x in range(10))
+print g
+#建L和g的区别仅在于最外层的[]和()，L是一个list，而g是一个generator。
+
+#我们可以直接打印出list的每一个元素，但我们怎么打印出generator的每一个元素呢？
+
+#如果要一个一个打印出来，可以通过next()函数获得generator的下一个返回值：
+for n in g:
+	print(n)

2017-04-24/generator/generator2_error.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+L=[x*x for x in range(10)]
+print L
+g=(x*x for x in range(10))
+print g
+#建L和g的区别仅在于最外层的[]和()，L是一个list，而g是一个generator。
+
+#我们可以直接打印出list的每一个元素，但我们怎么打印出generator的每一个元素呢？
+
+#如果要一个一个打印出来，可以通过next()函数获得generator的下一个返回值：
+
+next(g)
+next(g)
+next(g)
+next(g)
+next(g)
+next(g)
+next(g)
+next(g)
+next(g)
+next(g)
+next(g)

2017-04-24/high_order/high1.py

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+#!/bin/env python
+#-*- coding:utf-8 -*-
+#那么函数名是什么呢？函数名其实就是指向函数的变量！对于abs()这个函数，完全可以把函数名abs看成变量，它指向一个可以计算绝对值的函数！
+
+#如果把abs指向其他对象，会有什么情况发生？
+
+abs = 10
+print abs(-10)

2017-04-24/high_order/map_first.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def f(x):
+	return x * x
+print map(f,[1,2,3,4,5,6,7,8,9])

2017-04-24/high_order/transfer_func.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def add(x,y,f):
+	return f(x) + f(y)
+print add(-5,6,abs)
+#把函数作为参数传入，这样的函数称为高阶函数，函数式编程就是指这种高度抽象的编程范式

2017-04-24/map_fun/map_first.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def f(x):
+	return x * x
+print map(f,[1,2,3,4,5,6,7,8,9])

2017-04-24/map_fun/map_str.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+#这儿可以写中文
+print map(str,[1,2,3,4,5,6,7,8,9])

2017-04-24/map_fun/nap_reduce_char.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def fn(x,y):
+	return x * 10 + y
+def char2num(s):
+	return {'0':0,'1':1,'2':2,'3':3,'4':4,'5':5,'6':6,'7':7,'8':8,'9':9}[s]
+print reduce(fn, map(char2num,'13579'))

2017-04-24/map_fun/reduce_add.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def add(x,y):
+	return x + y
+print reduce(add,[1,3,5,7,9])

2017-04-24/map_fun/reduce_map.py

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+#!/bin/env pytho

2017-04-24/map_fun/ten_test.py

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+#! /bin/env python
+# -*- coding:utf-8 -*-
+def add(x, y):
+	return x*10 + y
+
+print reduce(add,[1,3,5,7,9])

2017-04-24/return_func/closure_fun.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def count():
+	fs=[]
+	for i in range(1,4):
+		def f(j):
+			def g():
+				return j*j
+			return g
+		fs.append(f(i))
+	return fs
+f1,f2,f3=count()
+print f1()
+print f2()
+print f3()
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2017-04-24/return_func/return_func1.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def calc_sum(*args):
+	ax=0
+	for n in args:
+		ax=ax+n
+	return ax
+def lazy_sum(*args):
+	def sum():
+		ax=0
+		for n in args:
+			ax=ax+n
+		return ax
+	return sum
+f1=lazy_sum(1,3,5,7,9)
+f2=lazy_sum(1,3,5,7,9)
+print f1==f2
+#print f
+#print f()

2017-04-24/sorted/ignoreStrSorted.py

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+#!/bin/env python
+def cmp_ignore_case(s1,s2):
+	u1 = s1.upper()
+	u2 = s2.upper()
+	if u1 < u2:
+		return 1
+	if u1 > u2:
+		return 1
+	return 0
+print sorted(['bob','about','Zoo','Credit'],cmp_ignore_case)

2017-04-24/sorted/reversed_cmp.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def reversed_cmp(x,y):
+	if x>y:
+		return -1
+	if x < y:
+		return 1
+	return 0
+print sorted([36,5,12,9,21],reversed_cmp)

2017-04-24/sorted/sort.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+print sorted([36,5,12,9,21])

2017-04-24/sorted/strSorted.py

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+#!/bin/env python
+print sorted(['bob','about','Zoo','Credit'])

2017-04-24p/f_lambda.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+f=lambda x:x*x
+print f
+print f(2)

2017-04-24p/map_lambda.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+print map(lambda x:x*x,[1,2,3,4,5,6,7,8,9])