python - 如何使用python获取文本文件中的表格格式数据

Question

我在文本文件中有表格数据，因此我尝试使用 python 获取数据，但我找不到每列之间的分隔符。请帮帮我。提前致谢。

数据可能是这样的:

Column1           Column2         Column3            Column4
----------------------------------------------------------------------------
apple fruits      banana fruits     orange fruits    grapes fruits
mango fruits      pineapple fruits                   blackberry fruits
                  blueberry fruits  currant fruits   papaya fruits
chico fruits                        peach fruits     pear fruits

我的预期结果是字典格式。

Answer 1

我假设数据在每条记录中的相同列对齐。

我把标题行和一个典型的行放在两个不同的变量中，你将从文件中读取它们

>>> a = 'Column1           Column2             Column3             Column4'
>>> b = 'apple fruits      banana fruits       orange fruits       grapes fruits'

i 是 header 中的索引列表，最初为空，inside 表示我们在列名称中

>>> i = []
>>> inside = False

我们计算字符数并检查我们是否在列名的开头

>>> for n, c in enumerate(a):
...     if c == ' ':
...         inside = False
...         continue
...     if not inside:
...         inside = True
...         i.append(n)
>>> i
[0, 18, 38, 58]

我们有列开头的索引，下一个列的开头在切片表示法中也是当前列的结尾——我们只需要最后一列的结尾，但使用切片表示法我们可以使用值 None

>>> [b[j:k].rstrip() for j, k in zip(i,i[1:]+[None])]
['apple fruits', 'banana fruits', 'orange fruits', 'grapes fruits']

当然，您必须对输入文件中的每个数据行应用相同的索引技巧。

P.S.:您可能想使用 itertools.zip_longest 方法

[... for j, k in itertools.zip_longest(i, i[1:])]

您可能希望缓存生成器以避免为每个数据行实例化它

cached_indices = list(itertools.zip_longest(i, i[1:]))
for line in data:
    c1, c2, c3, c4 = [... for i, j in cached_indices]

---

我尝试实现我在下面的评论中提出的建议，这是我最大的努力...

$ cat fetch.py
from itertools import count  # this import is necessary
from io import StringIO      # this one is needed to simulate an open file

# Your data, notice that some field in the last two lines is misaligned
data = '''\
Column1           Column2           Column3          Column4
----------------------------------------------------------------------------
apple fruits      banana fruits     orange fruits    grapes fruits
mango fruits      pineapple fruits                   blackberry fruits
                   blueberry fruits currant fruits   papaya fruits
chico fruits                        peach fruits    pear fruits
'''

f = StringIO(data) # you may have something like
                   # f = open('fruitfile.fixed')

# read the header line and skip a line                   
header = next(f).rstrip()
next(f) # skip a line

# a compact way of finding the starts of the columns
indices = [i for i, c0, c1 in zip(count(), ' '+header, header)
           if c0==' ' and c1!=' ']
# We are going to reuse zip(indices, indices[1:]+[None]), so we cache it
ranges = list(zip(indices, indices[1:]+[None]))

# we are ready for a loop on the lines of the file
for nl, line in enumerate(f, 3):
    if line == '\n': continue # don't process blank lines
    # extract the _raw_ fields from a line
    fields = [line[i:j] for i, j in ranges]
    # check that a non-all-blanks field does not start with a blank,
    # check that a field does not terminate wit anything but a space
    # or a newline
    if any((f[0]==' ' and f.rstrip()) or f[-1] not in ' \n' for f in fields):
        # signal the possibility of a misalignment
        print('Possible misalignment in line n.%d:'%nl)
        print('\t|'+header)
        print('\t|'+line.rstrip())
    # the else body is executed if all the fields are OK
    # what I do with the fields is just a possibility
    else:
        print('Data Line n.%d:'%nl)
        fields = [field.rstrip() for field in fields]
        for nf, field in enumerate(fields, 1):
            print('\tField n.%d:\t%r'%(nf, field))

$ python3 fetch.py 
Data Line n.3:
        Field n.1:      'apple fruits'
        Field n.2:      'banana fruits'
        Field n.3:      'orange fruits'
        Field n.4:      'grapes fruits'
Data Line n.4:
        Field n.1:      'mango fruits'
        Field n.2:      'pineapple fruits'
        Field n.3:      ''
        Field n.4:      'blackberry fruits'
Possible misalignment in line n.5:
        |Column1           Column2           Column3          Column4
        |                   blueberry fruits currant fruits   papaya fruits
Possible misalignment in line n.6:
        |Column1           Column2           Column3          Column4
        |chico fruits                        peach fruits    pear fruits
$