我有一个['A','B','C','D']和[1,2,3,4]的列表,这两个列表将始终具有相同数量的项目。我需要将每个字符串乘以它的数字,所以我要查找的最终产品是:将字符串列表乘以一个int列表,逐个元素
['A','B','B','C','C','C',' D','D','D','D']。
任何帮助,将不胜感激,谢谢。
我有一个['A','B','C','D']和[1,2,3,4]的列表,这两个列表将始终具有相同数量的项目。我需要将每个字符串乘以它的数字,所以我要查找的最终产品是:将字符串列表乘以一个int列表,逐个元素
['A','B','B','C','C','C',' D','D','D','D']。
任何帮助,将不胜感激,谢谢。
嵌套列表理解的工作太:
>>> l1 = ['A', 'B', 'C', 'D']
>>> l2 = [1, 2, 3, 4]
>>> [c for c, i in zip(l1, l2) for _ in range(i)]
['A', 'B', 'B', 'C', 'C', 'C', 'D', 'D', 'D', 'D']
在上面zip
返回(char, count)
元组:
>>> t = list(zip(l1, l2))
>>> t
[('A', 1), ('B', 2), ('C', 3), ('D', 4)]
然后为每一个所述第二for
循环执行count
倍于该字符添加到结果元组:
>>> [char for char, count in t for _ in range(count)]
['A', 'B', 'B', 'C', 'C', 'C', 'D', 'D', 'D', 'D']
我会用itertools.repeat
一个不错的,有效的实现:
>>> letters = ['A', 'B', 'C', 'D']
>>> numbers = [1, 2, 3, 4]
>>> import itertools
>>> result = []
>>> for letter, number in zip(letters, numbers):
... result.extend(itertools.repeat(letter, number))
...
>>> result
['A', 'B', 'B', 'C', 'C', 'C', 'D', 'D', 'D', 'D']
>>>
我也觉得是相当的可读性。
的代码是相当直接的,看在线评论
l1 = ['A', 'B', 'C', 'D']
l2 = [1, 2, 3, 4]
res = []
for i, x in enumerate(l1): # by enumerating you get both the item and its index
res += x * l2[i] # add the next item to the result list
print res
输出
['A', 'B', 'B', 'C', 'C', 'C', 'D', 'D', 'D', 'D']
您使用zip()
做像这样:
a = ['A', 'B', 'C', 'D']
b = [1, 2, 3, 4]
final = []
for k,v in zip(a,b):
final += [k for _ in range(v)]
print(final)
输出:
>>> ['A', 'B', 'B', 'C', 'C', 'C', 'D', 'D', 'D', 'D']
或者你也可以做到这一点,也使用zip()
和list comprehension
:
a = ['A', 'B', 'C', 'D']
b = [1, 2, 3, 4]
final = [k for k,v in zip(a,b) for _ in range(v)]
print(final)
输出:
>>> ['A', 'B', 'B', 'C', 'C', 'C', 'D', 'D', 'D', 'D']