python - 使用 csv 模块读取 ascii 分隔文本？

Question

你可能是也可能不是 aware的 ASCII delimited text ，它具有使用非键盘字符分隔字段和行的优势。

写出来很简单:

import csv

with open('ascii_delim.adt', 'w') as f:
    writer = csv.writer(f, delimiter=chr(31), lineterminator=chr(30))
    writer.writerow(('Sir Lancelot of Camelot', 'To seek the Holy Grail', 'blue'))
    writer.writerow(('Sir Galahad of Camelot', 'I seek the Grail', 'blue... no yellow!'))

而且，果然，你把东西倒出来了。但是，在阅读时，lineterminator 什么都不做，如果我尝试这样做:

open('ascii_delim.adt', newline=chr(30))

它抛出一个 ValueError: illegal newline value:

那么如何读取我的 ASCII 分隔文件？我是否只能做 line.split(chr(30))？

Answer 1

您可以通过有效地将文件中的行尾字符转换为换行符来实现 csv.reader 被硬编码以识别:

import csv

with open('ascii_delim.adt', 'w') as f:
    writer = csv.writer(f, delimiter=chr(31), lineterminator=chr(30))
    writer.writerow(('Sir Lancelot of Camelot', 'To seek the Holy Grail', 'blue'))
    writer.writerow(('Sir Galahad of Camelot', 'I seek the Grail', 'blue... no yellow!'))

def readlines(f, newline='\n'):
    while True:
        line = []
        while True:
            ch = f.read(1)
            if ch == '':  # end of file?
                return
            elif ch == newline:  # end of line?
                line.append('\n')
                break
            line.append(ch)
        yield ''.join(line)

with open('ascii_delim.adt', 'rb') as f:
    reader = csv.reader(readlines(f, newline=chr(30)), delimiter=chr(31))
    for row in reader:
        print row

输出:

['Sir Lancelot of Camelot', 'To seek the Holy Grail', 'blue']
['Sir Galahad of Camelot', 'I seek the Grail', 'blue... no yellow!']