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def sum(*args):
    return __builtins__.sum(filter(lambda x: type(x) == int, args))

print sum(1, 2, 3)

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def unique(integers):
    int_list = list(set(integers))
    int_list.sort(key = integers.index)
    return int_list
    
print unique([4, 1, 2, 4, 3])
# result [4, 1, 2, 3]

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a = range(1,11)
b = range(1,10)
c =  sum([item for item in a if item in b])
print c
# result: 45

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#吸血鬼数: http://zh.wikipedia.org/wiki/%E5%90%B8%E8%A1%80%E9%AC%BC%E6%95%B8

def vampire_test(x, y):
    print sorted(str(x) + str(y))
    return sorted(str(x * y)) == sorted(str(x) + str(y))
    
print vampire_test(21, 6)
# result: True

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# 这次终于算是比较满意的符合pythonic的解决方式了
def largest(n, xs):
  return sorted(xs)[len(xs)-n:]

print largest(2, [10,9,8,7,6,5,4,3,2,1])

# 不过看到一个更简洁的写法，好简洁，python真的是魅力无穷
def largest(n, xs):
  "Find the n highest elements in a list"
  

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# 这个是一个很程序化的写法，但是没有利用好python的特性
def number_of_occurrences(s, xs):
    num = 0
    for i in sorted(xs):
        if i == s:
            num += 1
    return num

# 这种写法就很pythonic
def number_of_occurrences2(s, xs):

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# 方法1
def square_sum(numbers):
    return sum(x**2 for x in numbers)

# 方法2
def square_sum2(numbers):
    return sum(map(lambda x: x**2, numbers))

# 方法3
def square_sum(numbers):

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import math  
 
def isPrime(n):  
  if n <= 1:  
    return False 
  for i in range(2, int(math.sqrt(n)) + 1):  
    if n % i == 0:  
      return False 
  return True 

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import re

def validPhoneNumber(phoneNumber):
    return bool(re.match(r"^(\([0-9]+\))? [0-9]+-[0-9]+$", phoneNumber))

# 使用正则表达式判断电话号码格式正确与否
#validPhoneNumber("(123) 456-7890")  =>  returns true
#validPhoneNumber("(1111)555 2345")  => returns false
#validPhoneNumber("(098) 123 4567")  => returns false

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def duplicate_count(s):
    return len([c for c in set(s.lower()) if s.lower().count(c)>1])
    
#test.assert_equals(duplicate_count("abcde"), 0)
#test.assert_equals(duplicate_count(""), 0)
#test.assert_equals(duplicate_count("abcdea"), 1)
#test.assert_equals(duplicate_count("indivisibility"), 1)
#test.assert_equals(duplicate_count("aabbcde"), 2)
#test.assert_equals(duplicate_count("aabbcdeB"), 2)
#test.assert_equals(duplicate_count("Indivisibilities"), 2)