python内置函数：lambda、map、filter简单介绍

def f(x): 
  return x**2 
print f(3) 
a = lambda x: x**2 
print a(3) 
a = lambda x,y: x+y 
print a(1,2) 
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def add1(a): 
  return a + 1 
def add2(a, b): 
  return a + b 
def add3(a, b, c): 
  return a + b + c 
a1 = [1,2,3,4,5] 
a2 = [1,2,3,4,5] 
a3 = [1,2,3,4,5] 
b = map(add1, a1) 
print b 
b = map(add2, a1, a2) 
print b 
b = map(add3, a1, a2, a3) 
print b 

def add1(a): 
  if a > 2: 
    return True 
  return False 
a1 = [1,2,3,4,5] 
b = filter(add1, a1) 
print b 

c = [b for b in a1 if b > 2] 
print c