sample.py

import csv

with open("file2.txt") as b:
    reader = csv.reader(b, delimiter="|")
    ranges = {range(int(start), int(end)): [three, four] for start, end, three, four, *_ in reader}

with open("file1.txt") as a, \
     open("file3.txt", 'wb') as outf:
    writer = csv.writer(outf, delimiter="|")
    for line in a:
        n = int(line.strip())
        for r, val in ranges.items():
            if n in r:
                writer.writerow([n] + val)