如何在Python中连接两个列表?

例子:

listone = [1, 2, 3]
listtwo = [4, 5, 6]

预期结果:

>>> joinedlist
[1, 2, 3, 4, 5, 6]

当前回答

您可以使用在列表对象上定义的append()方法:

mergedlist =[]
for elem in listone:
    mergedlist.append(elem)
for elem in listtwo:
    mergedlist.append(elem)

其他回答

如果您需要使用复杂的排序规则合并两个有序列表,您可能需要像下面的代码一样自行滚动(使用简单的排序规则以提高可读性:-)。

list1 = [1,2,5]
list2 = [2,3,4]
newlist = []

while list1 and list2:
    if list1[0] == list2[0]:
        newlist.append(list1.pop(0))
        list2.pop(0)
    elif list1[0] < list2[0]:
        newlist.append(list1.pop(0))
    else:
        newlist.append(list2.pop(0))

if list1:
    newlist.extend(list1)
if list2:
    newlist.extend(list2)

assert(newlist == [1, 2, 3, 4, 5])
 a = [1, 2, 3]
 b = [4, 5, 6]
     
 c = a + b
 print(c)

输出

>>> [1, 2, 3, 4, 5, 6]

在上面的代码中,“+”运算符用于将两个列表连接成一个列表。

另一种解决方案

 a = [1, 2, 3]
 b = [4, 5, 6]
 c = [] # Empty list in which we are going to append the values of list (a) and (b)

 for i in a:
     c.append(i)
 for j in b:
     c.append(j)

 print(c)

输出

>>> [1, 2, 3, 4, 5, 6]

您可以使用在列表对象上定义的append()方法:

mergedlist =[]
for elem in listone:
    mergedlist.append(elem)
for elem in listtwo:
    mergedlist.append(elem)

我能找到的加入列表的所有可能方法

import itertools

A = [1,3,5,7,9] + [2,4,6,8,10]

B = [1,3,5,7,9]
B.append([2,4,6,8,10])

C = [1,3,5,7,9]
C.extend([2,4,6,8,10])

D = list(zip([1,3,5,7,9],[2,4,6,8,10]))
E = [1,3,5,7,9]+[2,4,6,8,10]
F = list(set([1,3,5,7,9] + [2,4,6,8,10]))

G = []
for a in itertools.chain([1,3,5,7,9], [2,4,6,8,10]):
    G.append(a)


print("A: " + str(A))
print("B: " + str(B))
print("C: " + str(C))
print("D: " + str(D))
print("E: " + str(E))
print("F: " + str(F))
print("G: " + str(G))

输出

A: [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
B: [1, 3, 5, 7, 9, [2, 4, 6, 8, 10]]
C: [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
D: [(1, 2), (3, 4), (5, 6), (7, 8), (9, 10)]
E: [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]
F: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
G: [1, 3, 5, 7, 9, 2, 4, 6, 8, 10]

组合列表列表的一种非常简洁的方法是

list_of_lists = [[1,2,3], [4,5,6], [7,8,9]]
reduce(list.__add__, list_of_lists)

这给了我们

[1, 2, 3, 4, 5, 6, 7, 8, 9]