python - 读取 .txt 文件中的数据(不包括页眉和页脚)

Question

我有一个 .txt 文件，如下所示:

abcd this is the header
more header, nothing here I need
***********
column1    column2
=========  =========
  12.4       A
  34.6       mm
  1.3        um
=====================
footer, nothing that I need here
***** more text ******

我正在尝试读取列中的数据，每个列都有自己的列表，col1 = [12.4, 34.6, 1.3] 和 col2 = ['A', 'mm', 'um']。

这是我到目前为止所拥有的，但是当我运行代码时返回的唯一内容是“None”:

def readfile():
    y = sys.argv[1]

    z = open(y)
    for line in z:

        data = False
        if data == True:
            toks = line.split()
            print toks

        if line.startswith('=========  ========='):
            data = True
            continue

        if line.startswith('====================='):
            data = False
            break
print readfile()

有什么建议吗？

Answer 1

有很多方法可以做到这一点。

一种方法涉及:

1. 按行读取文件
2. 从读取的行中，找到包含列标题分隔符的行的索引(因为这也与页脚标题匹配)。
3. 然后，将数据存储在这些行之间。
4. 通过根据空格拆分这些行并将其存储到各自的列中来解析这些行。

像这样:

with open('data.dat', 'r') as f:
    lines = f.readlines()

    #This gets the limits of the lines that contain the header / footer delimiters
    #We can use the Column header delimiters double-time as the footer delimiter:
    #`=====================` also matches against this.
    #Note, the output size is supposed to be 2. If there are lines than contain this delimiter, you'll get problems
    limits = [idx for idx, data in enumerate(lines) if '=========' in data]

    #`data` now contains all the lines between these limits
    data = lines[limits[0]+1:limits[1]] 

    #Now, you can parse the lines into rows by splitting the line on whitespace
    rows = [line.split() for line in data]

    #Column 1 has float data, so we convert the string data to float
    col1 = [float(row[0]) for row in rows]

    #Column 2 is String data, so there is nothing further to do
    col2 = [row[1] for row in rows]

    print col1, col2

此输出(来自您的示例):

[12.4, 34.6, 1.3] #Column 1
['A', 'mm', 'um'] #Column 2