Python map/reduce函数

def f(x):
return x*x
a = map(f, [1, 2, 3, 4, 5])
b = map(f, (6, 7, 8, 9))
print a
print b
# [1, 4, 9, 16, 25]
# [36, 49, 64, 81]

# a = map(f, 1,2,3,4,5,6,7)
# print a
# Traceback (most recent call last):
# File "C:/workplace/SVC/DiskVideoTask/modules/test_mapReduce.py", line 8, in <module>
# a = map(f, 1,2,3,4,5,6,7)
# TypeError: argument 2 to map() must support iteration

def add(x,y):
　　return x+y

print reduce(add,[1,2,3,4,5])
# 15

def str2int(s):
　　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]
　　return reduce(fn,map(char2num,s))

print str2int(‘9876‘)

# 9876