python - 在 python 中将一个列表拆分为多个列表的有效方法是什么

Question

我想根据某些表达式将一个列表拆分为多个列表。

例如:

for elem in elemList:
     if elem>0 and elem<=3   add element to Partition1
     if elem>3 and elem<=6   add element to Partition2
     else                    add element to Partition3

如何高效地做到这一点？C++中有没有像erase、push_back in list之类复杂度为O(1)的？

或者有其他一些集合可以做到吗？

Answer 1

如果我理解正确，你可以使用list comprehensions :

Partition1 = [elem for elem in elemList if elem <= 3]
Partition2 = [elem for elem in elemList if elem > 3 and elem <= 6]
Partition3 = [elem for elem in elemList if elem > 6]

这是 Python 式的做法(对于 Partition1):

Partition1 = [] # creates an empty list
for elem in elemList: # for each element in list
    if elem > 0 and elem <= 3: # if they satisfy the condition
        Partition1.append(elem) # append them to the list

编辑:我在上面假设所有元素都大于零...如果其中一些不是，则 Partition1 和 Partition3 的列表理解必须是:

Partition1 = [elem for elem in elemList if elem > 0 and elem <= 3]
Partition3 = [elem for elem in elemList if elem > 6 or elem <= 0]