在Python中以特定顺序将列表值从列表插入到另一个列表中

Question

我试图将列表值从一个列表插入另一个列表，但按特定顺序，其中date [0]输入文本[1]，日期[1]输入文本[3]，依此类推。

dates=['21/11/2044', '31/12/2018', '23/9/3000', '25/12/2007']

text=['What are dates? ', ', is an example.\n', ', is another format as
well.\n', ', also exists, but is a bit ludicrous\n', ', are examples but more commonly used']

我试过这个方法：

for j in range(len(text)):
  for i in range(len(dates)):
   text.insert(int((j*2)+1), dates[i])

这是结果，这是不正确的：

['What are dates? ', '25/12/2007', '23/9/3000', '25/12/2007', '23/9/3000',
'25/12/2007', '23/9/3000', '25/12/2007', '23/9/3000', '25/12/2007',
'23/9/3000', '31/12/2018', '21/11/2044', '31/12/2018', '21/11/2044',
'31/12/2018', '21/11/2044', '31/12/2018', '21/11/2044', '31/12/2018',
'21/11/2044', ', is an example.\n', ', is another format as well.\n', ',
also exists, but is a bit ludicrous\n', ', are examples but more commonly used']

我试图找回一个如下所示的列表：

['What are dates? ','21/11/2044', 'is an example.\n','31/12/2018', ', is
another format as well.\n','23/9/3000', ', also exists, but is a bit
ludicrous\n', '25/12/2007',', are examples but more commonly used']

有没有办法按我想要的方式将日期[i]插入文本[2 * j + 1]？ 我是否应该使用for循环，还是有另一种方式而不是在日期中列出所有内容？

Answer 1

一种更简单的方法是使用Python 3.x中的itertools.zip_longest （或Python 2.x中的izip_longest ）：

>>> from itertools import zip_longest # for Python 3.x

>>> # For Python 2.x
>>> # from itertools import izip_longest

>>> dates=['21/11/2044', '31/12/2018', '23/9/3000', '25/12/2007']
>>> text=['What are dates? ', ', is an example.\n', ', is another format as well.\n', ', also exists, but is a bit ludicrous\n', ', are examples but more commonly used']

>>> [w for x in zip_longest(text, dates, fillvalue='') for w in x if w]
['What are dates? ', '21/11/2044', ', is an example.\n', '31/12/2018', ', is another format as well.\n', '23/9/3000', ', also exists, but is a bit ludicrous\n', '25/12/2007', ', are examples but more commonly used']

---

你的代码的问题是你有嵌套for循环，这就是为什么对于j每个索引，所有dates值都会被添加。

Answer 2

对于想要在每个其他元素中拟合日期的具体示例，您可以使用zip ：

parts = zip(['a', 'b', 'c', 'd'], ['d1', 'd2', 'd3'])
text = [x for y in parts for x in y]
# ['a', 'd1', 'b', 'd2', 'c', 'd3']

您可能需要使用itertools.izip_longest和/或处理列表之间的不等长度，否则您将看到上面的结果，其中'd'不在末尾。 第二行是丑陋的列表理解魔术，以平整列表列表。

Answer 3

您可以使用：

result = [ ]
for x in enumerate(dates, text):
   result.append(dates[x]).append(text[x])

Answer 4

双循环是这里的问题; 只使用一个for循环，如

for i in range(len(dates)):
    text.insert(int((i*2)+1), dates[i])

应该做的伎俩。

但是，如果您计划将第二个列表作为字符串结束，则使用.format可能更简单，如

text = 'Date with one format is {} and date with another format is {}.'.format(*dates)

哪个会给你

'Date with one format is 21/11/2044 and date with another format is 31/12/2018.'

Answer 5

也许它不是最优雅的版本，但这可以作为例如：

from itertools import zip_longest


dates=['21/11/2044', '31/12/2018', '23/9/3000', '25/12/2007']

text=['What are dates? ', ', is an example.\n', ', is another format as well.\n', ', also exists, but is a bit ludicrous\n', ', are examples but more commonly used']


l3 = list()
for i, j in zip_longest(text, dates, fillvalue=None):
    if i is not None:
        l3.append(i)
    if j is not None:
        l3.append(j)

print(l3)

来自标准itertools模块的zip_longest将2个不均匀长度的列表拉在一起，并用“fillvalue”填充缺失值。 如果你只丢弃那个fillvalue，你就可以去了。

Answer 6

一个很容易理解的简单解决方案

counter = 0
while counter < len(dates):
    text.insert(counter + counter + 1, dates[counter])
    counter += 1

实质上， .insert()用于追加到特定位置的列表。