0

我有一个包含键值对的文本文件，最后两个键值对包含类似 JSON 的对象，我想将它们拆分为列并与其他值一起写入，使用键作为列标题。数据文件的前三行input.txt如下所示：

InnerDiameterOrWidth::0.1,InnerHeight::0.1,Length2dCenterToCenter::44.6743867864386,Length3dCenterToCenter::44.6768028159989,Tag::<NULL>,{StartPoint::7858.35924983374[%2C]1703.69341358077[%2C]-3.075},{EndPoint::7822.85045874375[%2C]1730.80294308742[%2C]-3.53962362760298}
InnerDiameterOrWidth::0.1,InnerHeight::0.1,Length2dCenterToCenter::57.8689351603823,Length3dCenterToCenter::57.8700464193429,Tag::<NULL>,{StartPoint::7793.52927597915[%2C]1680.91224357457[%2C]-3.075},{EndPoint::7822.85045874375[%2C]1730.80294308742[%2C]-3.43363070193163}
InnerDiameterOrWidth::0.1,InnerHeight::0.1,Length2dCenterToCenter::68.7161350545728,Length3dCenterToCenter::68.7172034962765,Tag::<NULL>,{StartPoint::7858.35924983374[%2C]1703.69341358077[%2C]-3.075},{EndPoint::7793.52927597915[%2C]1680.91224357457[%2C]-3.45819643838485}

我们最终想出了一些可行的方法，但一定有更好的方法：

import csv
with open('input.txt', 'rb') as fin, open('output.csv', 'wb') as fout:
    reader = csv.reader(fin)
    writer = csv.writer(fout)
    for i, line in enumerate(reader):
        mysplit = [item.split('::') for item in line if item.strip()]
        if not mysplit: # blank line
            continue
        keys, vals = zip(*mysplit)
        start_vals = [item.split('[%2C]') for item in mysplit[-2]]
        end_vals = [item.split('[%2C]') for item in mysplit[-1]]
        a=list(keys[0:-2])
        a.extend(['start1','start2','start3','end1','end2','end3'])
        b=list(vals[0:-2])
        b.append(start_vals[1][0])
        b.append(start_vals[1][1])
        b.append(start_vals[1][2][:-1])
        b.append(end_vals[1][0])
        b.append(end_vals[1][1])
        b.append(end_vals[1][2][:-1])
        if i == 0:
            # if first line: write header
            writer.writerow(a)
        writer.writerow(b)

output.csv生成如下所示的输出文件

InnerDiameterOrWidth,InnerHeight,Length2dCenterToCenter,Length3dCenterToCenter,Tag,start1,start2,start3,end1,end2,end3
0.1,0.1,44.6743867864386,44.6768028159989,<NULL>,7858.35924983374,1703.69341358077,-3.075,7822.85045874375,1730.80294308742,-3.53962362760298
0.1,0.1,57.8689351603823,57.8700464193429,<NULL>,7793.52927597915,1680.91224357457,-3.075,7822.85045874375,1730.80294308742,-3.43363070193163
0.1,0.1,68.7161350545728,68.7172034962765,<NULL>,7858.35924983374,1703.69341358077,-3.075,7793.52927597915,1680.91224357457,-3.45819643838485

我们以后不想写这样的代码。

读取这样的数据的最佳方法是什么？

4

1 回答 1

1

我会使用：

from itertools import chain
import csv

_header_translate = {
    'StartPoint': ('start1', 'start2', 'start3'),
    'EndPoint': ('end1', 'end2', 'end3')
}

def header(col):
    header = col.strip('{}').split('::', 1)[0]
    return _header_translate.get(header, (header,))

def cleancolumn(col):
    col = col.strip('{}').split('::', 1)[1]
    return col.split('[%2C]')

def chainedmap(func, row):
    return list(chain.from_iterable(map(func, row)))

with open('input.txt', 'rb') as fin, open('output.csv', 'wb') as fout:
    reader = csv.reader(fin)
    writer = csv.writer(fout)
    for i, row in enumerate(reader):
        if not i:  # first row, write header first
            writer.writerow(chainedmap(header, row))
        writer.writerow(chainedmap(cleancolumn, row))

The cleancolumn method takes any of your columns and returns a tuple (possibly with only one value) after removing the braces, removing everything before the first :: and splitting on the embedded 'comma'. By using itertools.chain.from_iterable() we turn the series of tuples generated from the columns into one list again for the csv writer.

When handling the first line we generate one header row from the same columns, replacing the StartPoint and EndPoint headers with the 6 expanded headers.

于 2013-03-04T21:30:15.743 回答