Question

我是Python初学者，正在寻求提取问题的帮助。

我有一堆文本文件，需要提取表达式的所有特殊组合（“ C” +“正好是9个数字”）并将它们写入包含文本文件名的文件中。我想捕捉的每一次出现的表达式都从新行的开头开始，以“ / n”结尾。

sample_text = """Some random text here 
and here
and here
C123456789
some random text here
C987654321
and here
and here"""

输出的外观（在输出文件中）

My_desired_output_file = "filename,C123456789,C987654321"

到目前为止，我的代码：

min_file_size = 5

def list_textfiles(directory, min_file_size): # Creates a list of all files stored in DIRECTORY ending on '.txt'
    textfiles = []
    for root, dirs, files in os.walk(directory):
        for name in files:
            filename = os.path.join(root, name)
            if os.stat(filename).st_size > min_file_size:
                textfiles.append(filename)

for filename in list_textfiles(temp_directory, min_file_size):         
    string = str(filename)
    text = infile.read()
    regex = ???
    with open(filename, 'w', encoding="utf-8") as outfile:
       outfile.write(regex)

Answer 1

您的正则表达式为'^C[0-9]{9}$'

^           start of line
C           exact match
[0-9]       any digit
{9}         9 times
$           end of line

Answer 2

import re

regex = re.compile('(^C\d{9})')
matches = []
with open('file.txt', 'r') as file:
    for line in file:
        line = line.strip()
        if regex.match(line):
            matches.append(line)

然后您可以根据需要将此列表写入文件。

Answer 3

怎么样：

import re

sample_text = """Some random text here 
and here
and here
C123456789
some random text here
C987654321
and here
and here"""

k = re.findall('(C\d{9})',sample_text)

print(k)

这将返回该模式的所有匹配项。如果您从文本中得出一行并存储目标组合。像这样：

已更新：

import glob
import os
import re

search = {}
os.chdir('/FolderWithTxTs')
for file in glob.glob("*.txt"):
    with open(file,'r') as f:
        data = [re.findall('(C\d{9})',i) for i in f]
        search.update({f.name:data})

print(search)

这将返回一个以文件名作为键和找到的匹配项列表的字典。

Python-使用Regex从文本中提取代码

3 个答案: