拆分和替换二维列表中的字符串

Question

我有一组数据如下图：

[['05-Feb-2001 12:00:01','A','<>TG:MIN MAX W1 GRN RED'],
 ['05-Feb-2001 12:00:01','B','MIN MAX'],
 ['05-Feb-2001 12:00:07','A','<i>TG:MAX MIN W2'],
 ['05-Feb-2001 12:00:07','C','MAX RED GRN'],
 ['05-Feb-2001 12:00:20','A','MIN MAX RED'],
 ['05-Feb-2001 12:01:00','A','<i>TG:MAX MIN RED GRN']]

如该行的 3 值所示，它可能包含也可能不包含“<>TG”。我想检测

"<i>"

并将其从字符串中拆分出来，然后将其添加成为第 4 列

所需的输出将是

[['05-Feb-2001 12:00:01', 'A', '<>TG:MIN MAX W1 GRN RED'],
 ['05-Feb-2001 12:00:01', 'B', 'MIN MAX'],
 ['05-Feb-2001 12:00:07', 'A', 'TG:MAX MIN W2', '<i>'],
 ['05-Feb-2001 12:00:07', 'C', 'MAX RED GRN'],
 ['05-Feb-2001 12:00:20', 'A', 'MIN MAX RED'],
 ['05-Feb-2001 12:01:00', 'A', 'TG:MAX MIN RED GRN', '<i>']]

请指教！

Answer 1

这对你有用吗？只需遍历子列表并就地更新。

for l in lst:
    if '<i>TG' in l[-1]:
        l[-1] = l[-1].replace('<i>', '')
        l.append('<i>')       

print(lst)

[['05-Feb-2001 12:00:01', 'A', '<>TG:MIN MAX W1 GRN RED'],
 ['05-Feb-2001 12:00:01', 'B', 'MIN MAX'],
 ['05-Feb-2001 12:00:07', 'A', 'TG:MAX MIN W2', '<i>'],
 ['05-Feb-2001 12:00:07', 'C', 'MAX RED GRN'],
 ['05-Feb-2001 12:00:20', 'A', 'MIN MAX RED'],
 ['05-Feb-2001 12:01:00', 'A', 'TG:MAX MIN RED GRN', '<i>']]

如果要检查字符串开头的标记，请更改

if '<i>TG' in l[-1]

到

if l[-1].startswith('<i>TG')

（您不需要正则表达式。）

Answer 2

更短，使用list comprehension:

print([[y if x!=2 else y.replace('<i>','') for x,y in enumerate(i)]+['<i>'] if '<i>' in i[-1] else i for i in lst])

或者如果想要在开头：

print([[y if x!=2 else y.lstrip('<i>') for x,y in enumerate(i)]+['<i>'] if i[-1].startswith('<i>') else i for i in lst])\

两者输出：

[['05-Feb-2001 12:00:01', 'A', '<>TG:MIN MAX W1 GRN RED'],
 ['05-Feb-2001 12:00:01', 'B', 'MIN MAX'],
 ['05-Feb-2001 12:00:07', 'A', 'TG:MAX MIN W2', '<i>'],
 ['05-Feb-2001 12:00:07', 'C', 'MAX RED GRN'],
 ['05-Feb-2001 12:00:20', 'A', 'MIN MAX RED'],
 ['05-Feb-2001 12:01:00', 'A', 'TG:MAX MIN RED GRN', '<i>']]

Answer 3

您可以编写一个函数来检查列表数据列表中的一个条目，然后map将其应用于列表：

data = [['05-Feb-2001 12:00:01','A','<>TG:MIN MAX W1 GRN RED'],
        ['05-Feb-2001 12:00:01','B','MIN MAX'],
        ['05-Feb-2001 12:00:07','A','<i>TG:MAX MIN W2'],
        ['05-Feb-2001 12:00:07','C','MAX RED GRN'],
        ['05-Feb-2001 12:00:20','A','MIN MAX RED'],
        ['05-Feb-2001 12:01:00','A','<i>TG:MAX MIN RED GRN']]

def separate(entry, separator='<i>', position=2):
    return [
        el.replace(separator, '') if idx==position else el for idx, el in enumerate(entry)] + (
            [] if not separator in entry[position] 
            else [separator]
        )

from itertools import repeat
map(separate, data, repeat('<i>'), repeat(2))

Out[26]: 
[['05-Feb-2001 12:00:01', 'A', '<>TG:MIN MAX W1 GRN RED'],
['05-Feb-2001 12:00:01', 'B', 'MIN MAX'],
['05-Feb-2001 12:00:07', 'A', 'TG:MAX MIN W2', '<i>'],
['05-Feb-2001 12:00:07', 'C', 'MAX RED GRN'],
['05-Feb-2001 12:00:20', 'A', 'MIN MAX RED'],
['05-Feb-2001 12:01:00', 'A', 'TG:MAX MIN RED GRN', '<i>']]

注意：如果您使用 python 2.x，则 repeat 需要额外的参数 times=len(data).

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