python - 用 pyparsing 匹配非空行

Question

我正在尝试制作一个小型应用程序，用于pyparsing从另一个程序生成的文件中提取数据。

这些文件具有以下格式。

SOME_KEYWORD:
line 1
line 2
line 3
line 4

ANOTHER_KEYWORD:
line a
line b
line c

我如何构造有助于提取line 1, line 2...line 4和line a..的语法line c？我正在尝试制作这样的建筑

Grammar = Keyword("SOME_KEYWORD:").supress() + NonEmptyLines + EmptyLine.supress() +\
         Keyword("ANOTHER_KEYWORD:").supress() + NonEmptyLines + EmptyLine.supress()

但我不知道如何定义NonEmptyLines和EmptyLine。谢谢。

Answer 1

我的看法：

    from pyparsing import *

    # matches and removes end of line
    EOL = LineEnd().suppress()

    # line starts, anything follows until EOL, fails on blank lines,
    line = LineStart() + SkipTo(LineEnd(), failOn=LineStart()+LineEnd()) + EOL

    lines = OneOrMore(line)

    # Group keyword probably helps grouping these items together, you can remove it
    parser = Keyword("SOME_KEYWORD:") + EOL + Group(lines) + Keyword("ANOTHER_KEYWORD:") + EOL + Group(lines)
    result = parser.parseFile('data.txt')
    print result

结果是：

['SOME_KEYWORD:', ['line 1', 'line 2', 'line 3', 'line 4'], 'ANOTHER_KEYWORD:', ['line a', 'line b', 'line c']]

Answer 2

这将带您大部分时间到达那里：

import pyparsing as pp

data = """
SOME_KEYWORD:
line 1
line 2
line 3
line 4

ANOTHER_KEYWORD:
line a
line b
line c
"""

some_kw = pp.Keyword('SOME_KEYWORD:').suppress()
another_kw = pp.Keyword('ANOTHER_KEYWORD:').suppress()
kw = pp.Optional(some_kw ^ another_kw)

# Hint from: http://pyparsing.wikispaces.com/message/view/home/21931601
lines = kw + pp.SkipTo(
    pp.LineEnd() + pp.OneOrMore(pp.LineEnd()) |
    pp.LineEnd() + pp.StringEnd() |
    pp.StringEnd()
)

result = lines.searchString(data.strip())
results_list = result.asList()
# => [['\nline 1\nline 2\nline 3\nline 4'], ['\nline a\nline b\nline c']]

在构建语法时，将部分分配给变量并在可能时引用它们确实很有帮助。