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]
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
如果使用的是NumPy,可以使用以下命令连接两个兼容维度的数组:
numpy.concatenate([a,b])
其他回答
您可以简单地使用+或+=运算符,如下所示:
a = [1, 2, 3]
b = [4, 5, 6]
c = a + b
Or:
c = []
a = [1, 2, 3]
b = [4, 5, 6]
c += (a + b)
此外,如果希望合并列表中的值是唯一的,可以执行以下操作:
c = list(set(a + b))
值得注意的是,itertools.chain函数接受可变数量的参数:
>>> l1 = ['a']; l2 = ['b', 'c']; l3 = ['d', 'e', 'f']
>>> [i for i in itertools.chain(l1, l2)]
['a', 'b', 'c']
>>> [i for i in itertools.chain(l1, l2, l3)]
['a', 'b', 'c', 'd', 'e', 'f']
如果输入是可迭代的(元组、列表、生成器等),则可以使用from_iteable类方法:
>>> il = [['a'], ['b', 'c'], ['d', 'e', 'f']]
>>> [i for i in itertools.chain.from_iterable(il)]
['a', 'b', 'c', 'd', 'e', 'f']
所以有两种简单的方法。
使用+:它从提供的列表中创建一个新列表
例子:
In [1]: a = [1, 2, 3]
In [2]: b = [4, 5, 6]
In [3]: a + b
Out[3]: [1, 2, 3, 4, 5, 6]
In [4]: %timeit a + b
10000000 loops, best of 3: 126 ns per loop
使用扩展:它将新列表附加到现有列表。这意味着它不会创建单独的列表。
例子:
In [1]: a = [1, 2, 3]
In [2]: b = [4, 5, 6]
In [3]: %timeit a.extend(b)
10000000 loops, best of 3: 91.1 ns per loop
因此,我们发现在两种最流行的方法中,extend是有效的。
这很简单,我认为它甚至在教程中显示了:
>>> listone = [1,2,3]
>>> listtwo = [4,5,6]
>>>
>>> listone + listtwo
[1, 2, 3, 4, 5, 6]
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]