Question

我的文件有交替的线条，和弦后跟歌词：

C       G                 Am
See the stone set in your eyes,
         F                   C
see the thorn twist in your side,
  G         Am F
I wait for you

如何合并后续行以产生如下输出，同时跟踪字符位置：

(C)See the (G)stone set in your (Am)eyes,
see the t(F)horn twist in your s(C)ide,
I (G)wait for y(Am)ou(F)

从How do I read two lines from a file at a time using python可以看出，一次迭代文件2行可以用

完成

with open('lyrics.txt') as f:
    for line1, line2 in zip(f, f):
        ...  # process lines

但如何合并线条，以便根据第1行的（弦长）字符位置分割第2行？一个简单的

chords = line1.split()

没有位置信息和

for i, c in enumerate(line1):
    ...

给出单独的字符，而不是和弦。

Answer 1

您可以使用regexp match objects从第1行提取和弦的位置和内容。必须小心边缘;相同的和弦可以在下一行继续，并且一行可以包含没有匹配歌词的和弦。这两种情况都可以在示例数据中找到。

import io
import re

# A chord is one or more consecutive non whitespace characters
CHORD = re.compile(r'\S+')

def inline_chords(lyrics):
    for chords, words in zip(lyrics, lyrics):
        # Produce a list of (position, chord) tuples
        cs = [
            # Handles chords that continue to next line.
            (0, None),
            # Unpack found chords with their positions.
            *((m.start(), m[0]) for m in CHORD.finditer(chords)),
            # Pair for the last chord. Slices rest of the words string.
            (None, None)
        ]
        # Remove newline.
        words = words[:-1]

        # Zip chords in order to get ranges for slicing lyrics.
        for (start, chord), (end, _) in zip(cs, cs[1:]):
            if start == end:
                continue

            # Extract the relevant lyrics.
            ws = words[start:end]

            if chord:
                yield f"({chord})"

            yield ws

        yield "\n"

可以不同地处理边缘，例如通过测试第一个和弦是否在循环之前 0 开始，但我觉得单个for循环可以使代码更清晰。

尝试一下：

test = """\
C       G                 Am
See the stone set in your eyes,
         F                   C
see the thorn twist in your side,
  G         Am F
I wait for you
"""

if __name__ == '__main__':
    with io.StringIO(test) as f:
        print("".join(list(inline_chords(f))))

生成所需的格式：

(C)See the (G)stone set in your (Am)eyes,
see the t(F)horn twist in your s(C)ide,
I (G)wait for y(Am)ou(F)

根据字符位置合并Python中的行

1 个答案: