Python 在正则表达式中使用变量

Question

对于我自己的项目，我有一个包含 20 万个英文单词的 .txt 文件。 我有一个名为WordCross （游戏）的 class，它将搜索具有某些字母作为参数的单词，假设我有字母 AXDEL P。我想返回一个包含这些字母的英文单词列表。 现在我偶然发现了一个问题。 我想使用正则表达式并将匹配的单词添加到“命中”列表中。 但是，我想不出一种方法来创建这个正则表达式。

这是我当前的代码：

import re
class WordCross:
    def __init__(self, a,b,c,d,e,f):
        file = open("english3.txt", "r")
        hits = []
        for words in file:
            if words.lower() == re.search("a", words):
                hits.append(words)
        hits.sort()
        print(hits)

test = WordCross("A", "B", "C", "D", "E", "F")

任何帮助将不胜感激， 亲切的问候， Douwe

Answer 1

如果您只想返回与传递给构造函数的所有字母匹配的单词，则需要使用re.match并向正则表达式添加一个行尾锚点。 您可以使用星号运算符 ( * ) 允许将任意数量的字母传递给构造函数（请参阅手册）。 在这个演示中，我模拟了使用字符串中的单词列表读取文件：

wordlist = '''
Founded in two thousand and eight Stack Overflow is the largest most trusted 
online community for anyone that codes to learn share their knowledge and 
build their careers More than fifty million unique visitors come to Stack Overflow
each month to help solve coding problems develop new skills and find job opportunities
'''.split()
wordlist = list(set(wordlist))

import re
class WordCross:
    def __init__(self, *letters):
        # file = open("english3.txt", "r")
        hits = []
        charset = f"[{''.join(letters)}]"
        regex = re.compile(rf"(?!.*({charset}).*\1){charset}+$", re.I)
        for word in wordlist:
            if regex.match(word) is not None:
                hits.append(word)
        hits.sort()
        print(hits)

test = WordCross("A", "C", "E", "H", "K", "T", "S")

Output：

['Stack', 'each', 'the']

Answer 2

我不确定您要使用什么正则表达式，但是使用简单的字符串替换来构建表达式是微不足道的。 您也可以更改 function 以接受任意数量的模式进行搜索。 希望这有所帮助。

import re
class WordCross:
    def __init__(self, *patterns):
        list_of_patterns = "|".join(patterns)
        reg_exp = r"({0})".format(list_of_patterns)
        print(reg_exp)
        file = open("english3.txt", "r")
        hits = []
        for words in file:
            if re.search(reg_exp, words):
                hits.append(words)
        hits.sort()
        print(hits)

test = WordCross("A", "B", "C", "D", "E", "F")

Answer 3

我假设您文件中的单词是行分隔的。

代码：

import re
from io import StringIO

source = '''
RegExr was created by gskinner.com, and is proudly hosted by Media Temple.
Edit the Expression & Text to see matches. Roll over matches or the expression for details. PCRE & JavaScript flavors of RegEx are supported. Validate your expression with Tests mode.
The side bar includes a Cheatsheet, full Reference, and Help. You can also Save & Share with the Community, and view patterns you create or favorite in My Patterns.
Explore results with the Tools below. Replace & List output custom results. Details lists capture groups. Explain describes your expression in plain English.
'''.split()  # assuming words are line-separated here.

file_simulation = StringIO('\n'.join(source))  # simulating file open


class WordCross:
    def __init__(self, *args):
        self.file = file_simulation
        self.hits = []

        for words in self.file:
            if re.search(f"[{''.join(args)}]", words.upper()):
                self.hits.append(words.strip())

        self.hits.sort()
        print(self.hits)


test = WordCross("A", "B", "C", "D", "E", "F")

结果：

['Cheatsheet,', 'Community,', ... 'view', 'was']

进程以退出代码 0 结束

Answer 4

几个建议：

• 我在这里看不到任何值得 class 的东西。 一个简单的 function 就足够了。

• 不要使用文件作为变量； 它是 python 内置的名称。

• 通常，当使用打开的文件句柄时，最好在 with 块中这样做。

未经测试：

import re
def WordCross(*patterns):
    pattern = "|".join(patterns)
    c_pattern = re.compile(pattern, re.IGNORECASE)
    with open("english3.txt") as fp:
        hits = [line for line in fp if c_pattern.search(line)]
    print(sorted(hits))