Python-сообщество

  
>>> lst = [1, 2, 3, 15, 10, 16, 4, 5]
>>> 
>>> for i, item in enumerate(lst):
...     if item < 15:
...         lst[i] *= 2
... 
>>> lst
[2, 4, 6, 15, 20, 16, 8, 10]
>>> 

  
>>> 
>>> lst = [1, 2, 3, 15, 10, 16, 4, 5]
>>> out = [((i < 15 and i * 2) or i) for i in lst]
>>> out
[2, 4, 6, 15, 20, 16, 8, 10]
>>>

  
>>> lst = [1, 2, 3, 15, 10, 16, 4, 5]
>>> out = list(map(lambda i: (i < 15 and i * 2) or i, lst))
>>> out
[2, 4, 6, 15, 20, 16, 8, 10]
>>>