Python列表推导

>>> numbers = range(10)                                               
>>> size = len(numbers)                                               
>>> evens = []                                                        
>>> i = 0                                                             
>>> while i < size:                                                   
...     if i % 2 == 0:                                                
...             evens.append(i)
...     i += 1                 
...                            
>>> evens                      
[0, 2, 4, 6, 8]       

         
>>> [i for i in range(10) if i%2 == 0]
[0, 2, 4, 6, 8]