所以你可以在执行任何操作之前至少迭代一次字符串列表（例如换行符分隔的文本）。然后你可以将空格的索引存储在3个单独的列表中。问题是你真的需要在知道end_blanks是什么之前迭代整个列表。

text = """

First Paragraph

Second Paragraph

Third Paragraph

"""

start_blanks = []
mid_blanks = []
end_blanks = []
start = True

for idx, line in enumerate(text.splitlines()):
    if start and line == "":
        start_blanks.append(idx)
    elif start and line != "":
        start = False
    elif line == "":
        end_blanks.append(idx)
    elif line != "":
        # append current end_blanks to mid_blanks and
        # reset end_blanks
        mid_blanks.extend(end_blanks)
        end_blanks = []

print(f"Start blanks are lines: {start_blanks}")
print(f"Mid blanks are lines: {mid_blanks}")
print(f"End blanks are lines: {end_blanks}")

• 产出 *

Start blanks are lines: [0, 1]
Mid blanks are lines: [3, 4, 6, 7]
End blanks are lines: [9]