我在Python 3.2中有一个下面的代码,我想在Python 2.7中运行它。我确实进行了转换(missing_elements
在两个版本中都放了代码),但是我不确定这是否是最有效的方法。基本上,如果函数的yield from
上半部和下半部有两个类似下面的调用,会发生什么情况missing_element
?是否将两个半部分(上半部分和下半部分)中的条目彼此追加到一个列表中,以便父递归函数与yield from
调用一起使用,并将两个半部分一起使用?
def missing_elements(L, start, end): # Python 3.2
if end - start <= 1:
if L[end] - L[start] > 1:
yield from range(L[start] + 1, L[end])
return
index = start + (end - start) // 2
# is the lower half consecutive?
consecutive_low = L[index] == L[start] + (index - start)
if not consecutive_low:
yield from missing_elements(L, start, index)
# is the upper part consecutive?
consecutive_high = L[index] == L[end] - (end - index)
if not consecutive_high:
yield from missing_elements(L, index, end)
def main():
L = [10, 11, 13, 14, 15, 16, 17, 18, 20]
print(list(missing_elements(L, 0, len(L)-1)))
L = range(10, 21)
print(list(missing_elements(L, 0, len(L)-1)))
def missing_elements(L, start, end): # Python 2.7
return_list = []
if end - start <= 1:
if L[end] - L[start] > 1:
return range(L[start] + 1, L[end])
index = start + (end - start) // 2
# is the lower half consecutive?
consecutive_low = L[index] == L[start] + (index - start)
if not consecutive_low:
return_list.append(missing_elements(L, start, index))
# is the upper part consecutive?
consecutive_high = L[index] == L[end] - (end - index)
if not consecutive_high:
return_list.append(missing_elements(L, index, end))
return return_list