在一个单词之前和之后输出字符，然后写入文件

Question

Im trying to get this code to find say 30 words before a specific word and 30 words after. then i want it to writ'e my output to a new file. i cant seem to figure out what i'm doing wrong as im pretty new to python. any suggestions are more than welcome.

def extract_text(file_name, to_find):
    file_in = open('School.txt', 'r')

    all_lines = file_in.readlines()
    file_in.close()

    new_text = all_text.replace ('\n',  '|')

    width = 30



to_find = 'boy'
new_text = all_text.replace ('\n',  '|')
while new_text.find(to_find) != -1:
    start = all_text.find(to_find)
    begin = start - width
    end = start + len(to_find) + width



    print(new_text[begin:end])
    out_put = new_text[begin:end]

    f = open("School_boy.txt","w")
    f.write(out_put)

    f.close()

Answer 1

For text parsing, I would recommend using regex:

import re

# Read the File
with open("file.txt", "r") as file:
    text = file.read()

# replace newline with blank
text.replace('\n', '')

# parse the text
result = re.findall(r'(?P<before>\w+ ){30}target(P?<after>\w+ ){30}', text)

From there, all 30 words before are in a group called 'before' and all 30 words after are in a group called 'after' the target word -- in this example 'target'. RegEx can be really specific or really generic, depending on the pattern used. For example, the code above only allows for one space after a word and no punctuation. For a guide on python regex: https://docs.python.org/3/howto/regex.html