Question

我需要编写一个函数get_specified_words(filename)，以从文本文件中获取小写单词的列表。必须满足以下所有条件：

包括所有小写字符序列，包括那些包含-或'字符以及以'结尾的字符字符。
排除以-结尾的单词。
该函数只能处理起点和终点标记线之间的线
使用此正则表达式从文件的每个相关行中提取单词：valid_line_words = re.findall("[a-z]+[-'][a-z]+|[a-z]+[']?|[a-z]+", line)
在使用正则表达式之前，请确保行字符串是小写字母。
打开文件进行读取时，请使用可选的编码参数。那就是您的打开文件调用应该看起来像open（filename，encoding ='utf-8'）。如果您的操作系统未将Python的默认编码设置为UTF-8，这将特别有用。

示例文本文件testing.txt包含以下内容：

That are after the start and should be dumped.
So should that

and that
and yes, that
*** START OF SYNTHETIC TEST CASE ***
Toby's code was rather "interesting", it had the following issues: short,
meaningless identifiers such as n1 and n; deep, complicated nesting;   
a doc-string drought; very long, rambling and unfocused functions; not 
enough spacing between functions; inconsistent spacing before and 
after operators, just like   this      here. Boy was he going to get a low
style mark.... Let's hope he asks his friend Bob to help him bring his code
up to an acceptable level.
*** END OF SYNTHETIC TEST CASE ***
This is after the end and should be ignored too.

Have a nice day.

这是我的代码：

import re

def stripped_lines(lines):
    for line in lines:
        stripped_line = line.rstrip('\n')
        yield stripped_line

def lines_from_file(fname):
    with open(fname, 'rt') as flines:
        for line in stripped_lines(flines):
            yield line

def is_marker_line(line, start='***', end='***'):
    min_len = len(start) + len(end)
    if len(line) < min_len:
        return False
    return line.startswith(start) and line.endswith(end)


def advance_past_next_marker(lines):
    for line in lines:
        if is_marker_line(line):
            break


def lines_before_next_marker(lines):
    valid_lines = []
    for line in lines:
        if is_marker_line(line):
            break
         valid_lines.append(re.findall("[a-z]+[-'][a-z]+|[a-z]+[']?|[a-z]+", line))
    for content_line in valid_lines:
        yield content_line


def lines_between_markers(lines):
    it = iter(lines)
    advance_past_next_marker(it)
    for line in lines_before_next_marker(it):
        yield line


def words(lines):
    text = '\n'.join(lines).lower().split()
    return text

def get_valid_words(fname):
    return words(lines_between_markers(lines_from_file(fname)))

# This must be executed
filename = "valid.txt"
all_words = get_valid_words(filename)
print(filename, "loaded ok.")
print("{} valid words found.".format(len(all_words)))
print("word list:")
print("\n".join(all_words))

这是我的输出：

 File "C:/Users/jj.py", line 45, in <module>
text = '\n'.join(lines).lower().split()
builtins.TypeError: sequence item 0: expected str instance, list found

这是预期的输出：

valid.txt loaded ok.
73 valid words found.
word list:
toby's
code
was
rather
interesting
it
had
the
following
issues
short
meaningless
identifiers
such
as
n
and
n
deep
complicated
nesting
a
doc-string
drought
very
long
rambling
and
unfocused
functions
not
enough
spacing
between
functions
inconsistent
spacing
before
and
after
operators
just
like
this
here
boy
was
he
going
to
get
a
low
style
mark
let's
hope
he
asks
his
friend
bob
to
help
him
bring
his
code
up
to
an
acceptable
level

我需要帮助使我的代码正常工作。任何帮助表示赞赏。

Answer 1

lines_between_markers(lines_from_file(fname))

为您提供有效单词列表的列表。

因此，您只需将其展平：

def words(lines):
    words_list = [w for line in lines for w in line]
    return words_list

做到了。

但是我认为您应该检查程序的设计：

lines_between_markers应该只在标记之间产生线条，但是它做得更多。正则表达式应在此函数的结果上使用，而不是在函数内部使用。

您没有做的事情：

在使用正则表达式之前，请确保行字符串是小写字母。

打开文件进行读取时，请使用可选的编码参数。   那就是您的打开文件调用应该看起来像open（filename，   encoding ='utf-8'）。

正则表达式以查找文件中的有效单词

1 个答案: