我试图在元组列表中添加一个新元组(按元组中的第一个元素排序),其中新元组包含列表中上一个元素和下一个元素的元素.
例：
oldList = [(3,10),(4,7),(5,5)] newList = [(3,5)]
(4,10)由(3,10)和(4,7)之间构建并添加.
Construct (x,y) from (a,y) and (x,b)
我已经尝试使用枚举()插入到特定的位置,但这并不真正让我访问下一个元素.
解决方法
oldList = [(3,5)]
def pair(lst):
# create two iterators
it1,it2 = iter(lst),iter(lst)
# move second to the second tuple
next(it2)
for ele in it1:
# yield original
yield ele
# yield first ele from next and first from current
yield (next(it2)[0],ele[1])
哪个会给你：
In [3]: oldList = [(3,5)] In [4]: list(pair(oldList)) Out[4]: [(3,5)]
显然,我们需要做一些错误处理来处理不同的可能情况.
如果您愿意,也可以使用单个迭代器：
def pair(lst):
it = iter(lst)
prev = next(it)
for ele in it:
yield prev
yield (prev[0],ele[1])
prev = ele
yield (prev[0],ele[1])
您可以使用itertools.tee代替调用iter：
from itertools import tee
def pair(lst):
# create two iterators
it1,it2 = tee(lst)
# move second to the second tuple
next(it2)
for ele in it1:
# yield original
yield ele
# yield first ele from next and first from current
yield (next(it2)[0],ele[1])