Python：如何拆分合并某些行的行答案

【问题标题】：Python: How to split lines merging some of the linesPython：如何拆分合并某些行的行
【发布时间】：2017-01-30 10:32:05
【问题描述】：

我想逐行处理一个字符串，但我想启用多行支持。这是示例文本：

First line
Second line
{{{
these three lines
I want to process
together
}}}
Last Line

我希望多行从{{{ 开始并在}}} 结束我以前是这样逐行处理的：

lines = [l for l in text.splitlines()]
print lines

现在这段代码输出：

['First line', 'Second line', '{{{', 'these three lines', 'I want to process', 'together', '}}}', 'Last Line']

我想以某种方式使lines 包含以下内容：

['First line', 'Second line', 'these three lines I want to process together', 'Last Line']

或者，更高级的示例

First Line
Second line
Third{{{line
fourth line
fifth}}}line
sixth line

在这种情况下，我希望行包含

['First Line', 'Second line', 'Third', 'line fourth line fifth', 'line', 'sixth line']

【问题讨论】：

尝试遍历当前输出，检查'{{{'，然后连接所有行，直到你到达'}}}'。

标签： python split multiline

【解决方案1】：

这是一个将输入文件对象作为参数的生成器，一次生成一行。它应该在同一行接受尽可能多的{{{ 和}}}，但不测试不平衡的结构：

def merge_lines(fd):
    concat = False
    for line in fd:
        while True:
            #print (line)
            if len(line.strip()) == 0: break
            if not concat:
                if ('{{{' in line):
                    deb, line = line.split('{{{', 1)
                    yield deb
                    concat = True
                    old = None
                else:
                    yield line.strip('\r\n')
                    line = ""
            if concat:
                if ('}}}' in line):
                    deb, line = line.split('}}}', 1)
                    concat = False
                    if old:
                        yield old.strip() + ' ' + deb
                    else: yield deb
                else:
                    if old:
                        old += ' ' + line.strip('\r\n')
                    else:
                        old = line.strip('\r\n')
                    line = ""

Python 3 中的示例：

>>> t = """First line
a{{{b}}}c{{{d
e
f}}}g{{{h
i}}}
j
k
"""
>>> for line in merge_lines(io.StringIO(t)): print(line)

First line
a
b
c
d e f
g
h i
j
k

【讨论】：

【解决方案2】：

使用正则表达式似乎是一个明智的解决方案 - 它为您提供了两个输入选项之间的灵活性

import re

only_line = '''First line
Second line
{{{
these three lines
I want to process
together
}}}
Last Line'''

mixed_line = '''First Line
Second line
Third{{{line
fourth line
fifth}}}line
sixth line'''

def curly_brackets(input_string):
    # regex - we want to match text before the backets, text in the brackets, and text after the brackets as three groups
    separate = list(re.findall('(.*)\{{3}(.*)\}{3}(.*)', input_string, re.DOTALL)[0])

    # 1-indexed item will be the value between brackets - replace carriage returns with spaces
    separate[1] = separate[1].replace('\n', ' ')

    # split according to new lines - there will be none in our bracketed section
    separate = [x.strip().split('\n') for x in separate]

    # flatten the lists down - each element of separate is currently a list
    return [x for sublist in separate for x in sublist]

print curly_brackets(only_line)
print curly_brackets(mixed_line)

这会返回：

['First line', 'Second line', 'these three lines I want to process together', 'Last Line']
['First Line', 'Second line', 'Third', 'line fourth line fifth', 'line', 'sixth line']

如果您有多组大括号，这将不起作用，但可以适应以迭代方式应用。

【讨论】：

【解决方案3】：

这是我的解决方案。它又长又简单。我希望也许有一种方法可以在几行内完成但是当}}} 和{{{ 在同一行时，它不会处理大小写

def _split_with_merging(text):
    lines = [l for l in text.splitlines() if l != ""]
    nlines = []
    multiline = False
    for l in lines:
        if multiline:
            if "}}}" in l:
                lparts = l.split("}}}")
                nlines[len(nlines) - 1] += lparts[0]
                if lparts[1] != "":
                    nlines.append(lparts[1])
                multiline = False
            else:
                nlines[len(nlines) - 1] += l
        else:
            if "{{{" in l:
                lparts = l.split("{{{")
                nlines.append(lparts[0])
                if lparts[1] != "":
                    nlines.append(lparts[1])
                multiline = True
            else:
                nlines.append(l)
    return nlines

【讨论】：

【解决方案4】：

我认为这可以作为您想要完成的任务的快速简单的解决方案：

text = """First line
Second line
{{{
these three lines
I want to process
together
}}}
Last Line"""

all_lines = [l for l in text.splitlines()]
final_list = []

nested = False

for line in all_lines:
    if line == "{{{":
        nested = True
        multiline = ""
        continue
    elif line == "}}}":
        nested = False
        final_list.append(multiline)
        continue


    if nested == True:        
        multiline = multiline + " " + line            
    else:
        final_list.append(line)


print(final_list)

可能不是有史以来最干净的代码，我认为我们应该将 multiline = multiline + " " + line 替换为 .format()，但我希望你明白这一点。

【讨论】：

哦...我现在注意到您还想处理“{{{”出现在其他文本之间的情况。这将需要进一步的工作:)

【解决方案5】：

def split(text):    
    lines = []
    while '{{{' in text:
        head, sep, tail = text.partition('{{{')
        lines.extend(head.splitlines())
        head, sep, tail = tail.partition('}}}')
        lines.append(head.replace('\n', ' ').strip())
        text = tail

    lines.extend(text.splitlines())
    return lines

【讨论】：

【解决方案6】：

你可以使用正则表达式，假设你对{{{ }}}}之间的行感兴趣

text = """First line
Second line
THIS{{{
these three lines
I want to process
together
}}}
Last Line"""

import re
match_obj = re.search('{{{(.*)}}}', text, re.DOTALL)
print match_obj.group(1)

或

r = re.compile('{{{(.*)}}}', flags=re.DOTALL)
print re.split(r, text)
# replace \n
split_list = re.split(r, text)
split_list = [l.replace('\n', '') for l in split_list]
print split_list

或

match_list = re.findall('{{{(.*)}}}', text, re.DOTALL)
match_list = [l.replace('\n', '') for l in match_list]
print match_list

如果您在给定文本中多次出现{{{ }}}，请通过添加“？”来使用非贪婪匹配例如{{{(.*?)}}}

【讨论】：

【解决方案7】：

我的 2 美分（使用 joint）：

ex1 = """First line
Second line
{{{
these three lines
I want to process
together
}}}
Last Line"""

ex2 = """First Line
Second line
Third{{{line
fourth line
fifth}}}line
sixth line"""

def parse_lines(txt, start_sep='{{{', end_sep='}}}'):
    depth = 0 # 1+ if we are inside a {{{ group
              # can be used to test unbalanced constructs
    lines = []
    current_line = ''
    n = len(txt)
    i = 0
    while i < n:
        c = txt[i]
        not_handled = True
        need_to_add = False
        if c == '\n': # end of line
            if depth == 0 : # save line and empty buffer
                need_to_add = True
            elif current_line != '': # add a space instead of the line break
                current_line = ''.join((current_line,' '))
            not_handled = False
            i += 1
        elif c == start_sep[0] and\
             txt[i:i+len(start_sep)] == start_sep:
             # ^ takes small advantage of lazy evaluation
             # (see questions/13960657)
                depth += 1
                need_to_add = True
                not_handled = False
                i += len(start_sep)
        elif c == end_sep[0] and\
             txt[i:i+len(end_sep)] == end_sep:
                depth -= 1
                need_to_add = True
                not_handled = False
                i += len(end_sep)
        if not_handled:
            current_line = ''.join((current_line,c))
            i += 1
        elif need_to_add and current_line != '':
            lines.append(current_line)
            current_line = ''
    if current_line != '': # add last line
        lines.append(current_line)
    return lines

返回：

>>> parse_lines(ex1)
['First line', 'Second line', 'these three lines I want to process together ', 'Last Line']
>>> parse_lines(ex2)
['First Line', 'Second line', 'Third', 'line fourth line fifth', 'line', 'sixth line']

请注意第一个示例中以'\n}}}' 结尾的多行上的额外' '。

【讨论】：

【解决方案8】：

使用in_multi 标志在循环中跟踪打开{{{ 和关闭}}} 直截了当：

def split_multi(s):
    lines = []
    in_multi = False
    for line in s.splitlines():
        if in_multi:
            if '}}}' in line:
                in_multi = False
                split = line.split('}}}')
                if split[0]:
                    tmp.append(split[0])
                lines.append(' '.join(tmp))
                if split[-1]:
                    lines.append(split[-1])
            else:
                tmp.append(line)
        else:
            if '{{{' in line:
                split = line.split('{{{')
                in_multi = True
                if split[0]:
                    lines.append(split[0])
                    if split[-1]:
                        tmp = [split[-1]]
                else:
                    tmp = []
            else:
                lines.append(line)

    return lines 


s1 = """First line
Second line
{{{
these three lines
I want to process
together
}}}
Last Line"""

s2 = """First Line
Second line
Third{{{line
fourth line
fifth}}}line
sixth line"""

print(split_multi(s1))
print(split_multi(s2))
#['First Line', 'Second line', 'Third', 'line fourth line fifth', 'line', 'sixth line']

输出：

['First line', 'Second line', 'these three lines I want to process together', 'Last Line']
['First Line', 'Second line', 'Third', 'line fourth line fifth', 'line', 'sixth line']

【讨论】：