io.py

def delimited(filename, delimiter=' ', bufsize=4096):
    '''
    Creates a generator of word from a file based on a delimiter (by default white space).
    '''
    
    buf = ''
    with open(filename) as file:
        while True:
            newbuf = file.read(bufsize)
            if not newbuf:
                yield buf
                return
            buf += newbuf
            words = buf.split(delimiter)
            for word in words[:-1]:
                yield word
            buf = words[-1]