just-input.py

import os

def clean(s):
    s = s.strip()
    if s.find('http://') == 0:
        s = s[7:]
    if s.find('www.') == 0:
        s = s[4:] 
    return s 

def baca():
    if os.path.exists(filename):
        f = open(filename)
        s = f.read()
        f.close()
        return s.splitlines()
    return []


def tulis():
    lines = baca()
    if new in lines:
        return
    lines.append(new)
    s = '\n'.join(lines)
    f = open(filename, 'w')
    f.write(s)
    f.close()
    return True


filename = 'data.txt'

while True:
    new = raw_input('Tulis: ')
    new = clean(new)
    if not new:
        break
    if tulis():
        print('Data sudah ditambahkan di %s' % filename)
    else:
        print('Data itu sudah ada di %s' % filename)