高阶函数的学习

Author: kangxiaoyu

2017-04-2-4/modules/1.txt

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+hello world

2017-04-2-4/modules/alias_module.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+' a est module '
+__author__='Kangxiaoxiao'
+
+try:
+    import cStringIO as StringIO
+except ImportError: # 导入失败会捕获到ImportError
+    import StringIO

2017-04-2-4/modules/helloModule.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+' a est module '
+__author__='Kangxiaoxiao'
+
+import sys
+def test():
+	args=sys.argv
+	if len(args)==1:
+		print 'Hello,world!'
+	elif len(args)==2:
+		print 'Hello,%s!' % args[1]
+	else:
+		print 'Too many arguments!'
+if __name__=='__main__':
+	test()

2017-04-2-4/modules/helloModule.pyc

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+try:
+	f=open('/root/python1/python_execise/2017-04-2-4/modules/1.txt','r')
+	print f.read()
+finally:
+	if f:
+		f.close()
+

2017-04-2-4/modules/read1.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+import os
+print os.name

2017-04-2-4/operata_file/print_os.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+import os
+print os.uname()

2017-04-2-4/operata_file/print_os_name.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def now():
+	print('2017-04-25')
+f=now
+f()
+print now.__name__
+print f.__name__

2017-04-25/am/decorator/decorator.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def now():
+	print('2017-04-25')
+f=now
+f()
+print now.__name__
+print f.__name__
+
+def log(func):
+	def wrapper(*args,**kw):
+		print('call %s():' % func.__name__)
+		return func(*args,**kw)
+	return wrapper
+@log
+def now():
+	print('2017-04-25')
+if __name__=='__main__':
+	now()

2017-04-25/am/decorator/decorator_test.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def log(text):
+	def decorator(func):
+		def wrapper(*args,**kw):
+			print('%s %s():' % (text, func.__name__))
+			return func(*args,**kw)
+		return wrapper
+	return decorator
+@log('execute')
+def now():
+	print('2017-04-25')
+if __name__=='__main__':
+	now()

2017-04-25/am/decorator/decorator_text.py

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

2017-04-25/am/filter_1/filter_test.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def is_odd(n):
+	return n % 2 == 1
+def not_empty(s):
+	return s and s.strip()
+if __name__=='__main__':
+	print filter(is_odd,[1,2,4,5,6,9,10,15])
+	print filter(not_empty,['A','','B',None,'C',' '])

2017-04-25/am/filter_1/filter_test_empty.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def f(x):
+	return x*x
+if __name__=='__main__':
+	L=[]
+	for n in [1,2,3,4,5,6,7,8,9]:
+		L.append(f(n))
+	print L
+
+

2017-04-25/am/map_reduce/for_math_function.py

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+#!/bin/env python
+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]
+def str2int(s):
+	return reduce(lambda x,y:x*10+y,map(char2num,s))
+if __name__=='__main__':
+	r=str2int('13579')
+	print r

2017-04-25/am/map_reduce/lambda_map_reduce.py

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

2017-04-25/am/map_reduce/math_function.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def num_l_to_char_l():
+	r=map(str,[1,2,3,4,5,6,7,8,9])
+	print r
+if __name__=='__main__':
+	num_l_to_char_l()

2017-04-25/am/map_reduce/numlist_to_charlist.py

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

2017-04-25/am/map_reduce/reduce_add.py

@@ -0,0 +1,7 @@
+#!/bin/env python
+# -*- coding:utf-8 -*-
+def fn(x,y):
+	return x*10 + y
+if __name__=='__main__':
+	r=reduce(fn,[1,3,5,7,9])
+	print r

2017-04-25/am/map_reduce/reduce_fn.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]
+if __name__=='__main__':
+	r=reduce(fn,map(char2num,'13579'))
+	print r

2017-04-25/am/map_reduce/reduce_fn_char2num.py

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+#再看reduce的用法。
+#reduce把一个函数作用在一个序列[x1, x2, x3...]上，这个函数必须接收两个参数，i
+#reduce把结果继续和序列的下一个元素做累积计算，其效果就

2017-04-25/am/map_reduce/reduce_note.txt

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+方法是再创建一个函数，用该函数的参数绑定循环变量当前的值，无论该循环变量后续如何更改，已绑定到函数参数的值不变：

2017-04-25/am/return_function/close.txt

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def count():
+	def f(j):
+		def g():
+			return j*j
+		return g
+	fs=[]
+	for i in range(1,4):
+		fs.append(f(i))
+	return fs
+if __name__=='__main__':
+	f1,f2,f3=count()
+	print f1()
+	print f2()
+	print f3()
+

2017-04-25/am/return_function/close_wait.py

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

2017-04-25/am/return_function/return_function.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def count():
+	fs=[]
+	for i in range(1,4):
+		def f():
+			return i*i
+		fs.append(f)
+	return fs
+if __name__=='__main__':
+	f1,f2,f3=count();
+	print f1()
+	print f2()
+	print f3()
+

2017-04-25/am/return_function/return_funtions_tired.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
+if __name__=='__main__':
+	print sorted([36,21,12,9,21],reversed_cmp)

2017-04-25/am/sorted/.reverse_sorted.py.swp

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+def sorted_test():
+	r=sorted([36,5,12,9,21])
+	return r
+if __name__=='__main__':
+	r=sorted_test()
+	print r

2017-04-25/am/sorted/reverse_sorted.py

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+
+def test():
+	f=abs
+	print f(-10)
+if __name__=='__main__':
+	test()
+

2017-04-25/am/sorted_buildin.py

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+高阶函数英文叫Higher-orger function. 什么是高阶函数，
+变量可以指向函数。
+

2017-04-25/am/variable_function.py

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+当函数的参数个数太多，需要简化时，使用functools.partial可以创建一个新的函数，这个新函数可以固定住原函数的部分参数，从而在调用时更简单。

2017-04-25/am/高阶函数.txt

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+#!/bin/env python
+# -*- coding:utf-8 -*-
+import functools
+if __name__=='__main__':
+	int2=functools.partial(int,base=2)
+	print int2('1000000')
+	print int2('1010101')