具有多个值的先行断言

Question

我有以下文字：

[red]

aaa [bbb] hello

[blue]

aaa

[green]

ccc

我想提取 header 部分之间的所有文本。我尝试了从特定部分 header 匹配到 header 列表中的另一个 header 的前瞻断言：

keys = ('red', 'blue', 'green')
for key in keys:
    match = re.search(r'\[' + key + r'\](.*)(?=(?:' + '|'.join(keys) + r'|$))',
                      text, flags=re.DOTALL)

    print(key, match.group(1))

我遗漏了一些东西，因为它不匹配任何东西。有什么想法吗？

Answer 1

您可以使用正则表达式查找所有内容！您可以将您的部分和其中的值组合在一起，例如

>>> import re
>>> print re.findall(r'\[(\w*)\]([\w \n]*)',text)
[('red', '\n\naaa '), ('bbb', ' hello\n\n'), ('blue', '\n\naaa\n\n'), ('green', '')]

此处用于您的部分 \[(\w*)\] 和 ([\w \n]*) 用于您部分中的内容。有了这个结果，您可以删除或替换多余的换行符！

希望对您有所帮助！

Answer 2

也许这种方法可行：

keys = ('red', 'blue', 'green')

res = re.findall(r'\[\w+\].?|([\w\[\] ]+)', text)
res = [x for x in res if x]

for n in range(len(keys)):
    print(keys[n], res[n])

结果：

('red', 'aaa [bbb] hello')
('blue', 'aaa')
('green', 'ccc')

示例：

https://regex101.com/r/p55ckh/1

Answer 3

最后，我决定不使用正则表达式来匹配部分内容:

# Walk through the file line by line and collect text from the specific sections
keys = ('red', 'blue', 'green')
last_section = ''
for line in text.splitlines():
    if line.startswith('#'):
        continue

    match = re.match(r'^\[(' + '|'.join(keys) + ')\]', line)
    if match:
        last_section = match.group(1)
        continue

    if last_section:
        new_contents[last_section] += '\n' + line

for section in new_contents:
    new_contents[section] = new_contents[section].strip()

Answer 4

一种字符串处理方法，无论您在文本中键入的顺序如何。如果您不想使用正则表达式，希望对您有所帮助！

text = '[red]\naaa [bbb] hello\n[blue]\naaa\n[green]\nccc'

# keys = ('red', 'blue', 'green')
# keys = ('blue', 'red', 'green')
# keys = ('green', 'red', 'blue')
keys = ('green', 'blue', 'red')
# store key and index of key tuple
index_key_tuples = []

for key in keys:
    index = text.find('[' + key + ']')
    if index != -1:
        index_key_tuples.append((index, key))
# sort the index key tuple
index_key_tuples.sort()

i = 0
size = len(index_key_tuples)
while i < size - 1:
    # start index of content of key
    item = index_key_tuples[i]
    key = item[1]
    start_index = item[0] + len(key) + 2  # 2 is for square bracket
    # end index of content of key
    next_item = index_key_tuples[i + 1]
    end_index = next_item[0]
    # content of key
    key_content = text[start_index:end_index].strip()
    print(key, key_content)
    i += 1

# handle the last key
last_item = index_key_tuples[size-1]
key = last_item[1]
start_index = last_item[0] + len(key) + 2
key_content = text[start_index:].strip()
print(key, key_content)

具有多个值的先行断言

Lookahead assertion with multiple values

python

regex

lookahead