Вырвать строки из txt по количеству символов в другой txt

with open ("main.txt", encoding="utf-8") as main_fp:
   for line in main_fp:
       len_line = len(line)-1
       name_file = str(len(line)-1) + ".txt"
       if len_line < 8 or len_line > 14:
           continue;
       with open (name_file, 'a+') as fp:
            fp.write(line)

with open("main.txt", "r", encoding="utf-8" ) as f:
    text = f.read().split()
    
    for x in range(len(text)):
        s = text[x]
        k = len(s)
        print(k)
        with open(f'{k}.txt', 'a') as f:
            f.write(f"{s}\n")
    
print(text)

with open("a.txt", "r") as f:
    text = f.read().split()
    
w8,w9,w10,w11,w12,w13,w14 = [],[],[],[],[],[],[]
 
for x in range(len(text)):
    s = text[x]
    k = len(s)
    if k < 8 or k > 14:
           continue;
    if 8 <= k <= 14:
        if k == 8:
            if s not in w8:
                w8.append(s)
        if k == 9:
            if s not in w9:
                w9.append(s)
        if k == 10:
            if s not in w10:
                w10.append(s)
        if k == 11:
            if s not in w11:
                w11.append(s)
        if k == 12:
            if s not in w12:
                w12.append(s)
        if k == 13:
            if s not in w13:
                w13.append(s)
        if k == 14:
            if s not in w14:
                w14.append(s)
 
with open(f'{8}.txt', 'a') as f:  
    f.write("\n".join(w8))
with open(f'{9}.txt', 'a') as f:  
    f.write("\n".join(w9))
with open(f'{10}.txt', 'a') as f:  
    f.write("\n".join(w10))
with open(f'{11}.txt', 'a') as f:  
    f.write("\n".join(w11))
with open(f'{12}.txt', 'a') as f:  
    f.write("\n".join(w12))
with open(f'{13}.txt', 'a') as f:  
    f.write("\n".join(w13))
with open(f'{14}.txt', 'a') as f:  
    f.write("\n".join(w14))
print(w8)
print(w9)
print(w10)
print(w11)
print(w12)
print(w13)
print(w14)

with open('in.txt','r') as f:
    txt = f.read().split()
    
for i in range(8, 15):
    with open(f'{i}.txt', 'w') as f:
        f.write('\n'.join(list(filter(lambda x: len(x)==i, txt))))