Question

我早上大部分时间都没有解决这个简单的问题。使用python，我想解析看起来像这样的数据文件：

# This is an example comment line, it starts with a '#' character.
# There can be a variable number of comments between each data set.
# Comments "go with" the data set that comes after them.
# The first data set starts on the next line:
0.0 1.0
1.0 2.0
2.0 3.0
3.0 4.0

# Data sets are followed by variable amounts of white space.
# The second data set starts after this comment
5.0 6.0
6.0 7.0


# One more data set.
7.0 8.0
8.0 9.0

我想要的python代码会将上面的示例解析为三个“块”，将它们存储为列表的元素。各个代码块本身可以存储为行列表，有或没有注释行，无论如何。手动方式是这样做：

#! /usr/bin/env python

# Read in data, seperate into rows_alldata
f=open("example")
rows = f.read().split('\n')
f.close()

# Do you haz teh codez?
datasets=[]
datasets.append(rows[0:8])
datasets.append(rows[9:13])
datasets.append(rows[15:18])

我正在寻找一种支持可变数量和长度的数据集的更通用的解决方案。我已经尝试了几个非pythonic外观循环的灾难。我认为最好不要与他们混淆我的问题;这是工作而不是“家庭作业”。

Answer 1

使用groupby。

from itertools import groupby

def contains_data(ln):
    # just an example; there are smarter ways to do this
    return ln[0] not in "#\n"

with open("example") as f:
    datasets = [[ln.split() for ln in group]
                for has_data, group in groupby(f, contains_data)
                if has_data]

Answer 2

datasets = [[]]
with open('/tmp/spam.txt') as f:
  for line in f:
    if line.startswith('#'):
      if datasets[-1] != []:
        # we are in a new block
        datasets.append([])
    else:
      stripped_line = line.strip()
      if stripped_line:
        datasets[-1].append(stripped_line)

Answer 3

import pprint

with open("test.txt") as fh:
    codes = []
    codeblock = []

    for line in fh:
        stripped_line = line.strip()

        if not stripped_line:
            continue

        if stripped_line.startswith("#"):
            if codeblock:
                codes.append(codeblock)
                codeblock = []

        else:
            codeblock.append(stripped_line.split(" "))

    if codeblock:
        codes.append(codeblock)

pprint.pprint(codes)

输出：

[[['0.0', '1.0'], ['1.0', '2.0'], ['2.0', '3.0'], ['3.0', '4.0']],
 [['5.0', '6.0'], ['6.0', '7.0']],
 [['7.0', '8.0'], ['8.0', '9.0']]]

Answer 4

datasets = []
with open('example') as f:
    for line in f:
        if line and not line.startswith('#'):
            datasets.append(line.split())

如何基于Python中的注释块拆分文本文件？

4 个答案: