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""" |
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Markov chain simulation of words or characters. |
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""" |
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class Markov: |
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def __init__(self, histsize, choice): |
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self.histsize = histsize |
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self.choice = choice |
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self.trans = {} |
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def add(self, state, next): |
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self.trans.setdefault(state, []).append(next) |
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def put(self, seq): |
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n = self.histsize |
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add = self.add |
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add(None, seq[:0]) |
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for i in range(len(seq)): |
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add(seq[max(0, i-n):i], seq[i:i+1]) |
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add(seq[len(seq)-n:], None) |
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def get(self): |
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choice = self.choice |
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trans = self.trans |
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n = self.histsize |
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seq = choice(trans[None]) |
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while True: |
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subseq = seq[max(0, len(seq)-n):] |
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options = trans[subseq] |
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next = choice(options) |
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if not next: |
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break |
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seq += next |
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return seq |
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def test(): |
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import sys, random, getopt |
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args = sys.argv[1:] |
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try: |
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opts, args = getopt.getopt(args, '0123456789cdwq') |
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except getopt.error: |
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print('Usage: %s [-#] [-cddqw] [file] ...' % sys.argv[0]) |
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print('Options:') |
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print('-#: 1-digit history size (default 2)') |
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print('-c: characters (default)') |
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print('-w: words') |
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print('-d: more debugging output') |
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print('-q: no debugging output') |
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print('Input files (default stdin) are split in paragraphs') |
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print('separated blank lines and each paragraph is split') |
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print('in words by whitespace, then reconcatenated with') |
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print('exactly one space separating words.') |
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print('Output consists of paragraphs separated by blank') |
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print('lines, where lines are no longer than 72 characters.') |
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sys.exit(2) |
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histsize = 2 |
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do_words = False |
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debug = 1 |
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for o, a in opts: |
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if '-0' <= o <= '-9': histsize = int(o[1:]) |
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if o == '-c': do_words = False |
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if o == '-d': debug += 1 |
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if o == '-q': debug = 0 |
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if o == '-w': do_words = True |
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if not args: |
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args = ['-'] |
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m = Markov(histsize, random.choice) |
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try: |
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for filename in args: |
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if filename == '-': |
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f = sys.stdin |
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if f.isatty(): |
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print('Sorry, need stdin from file') |
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continue |
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else: |
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f = open(filename, 'r') |
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with f: |
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if debug: print('processing', filename, '...') |
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text = f.read() |
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paralist = text.split('\n\n') |
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for para in paralist: |
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if debug > 1: print('feeding ...') |
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words = para.split() |
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if words: |
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if do_words: |
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data = tuple(words) |
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else: |
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data = ' '.join(words) |
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m.put(data) |
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except KeyboardInterrupt: |
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print('Interrupted -- continue with data read so far') |
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if not m.trans: |
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print('No valid input files') |
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return |
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if debug: print('done.') |
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if debug > 1: |
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for key in m.trans.keys(): |
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if key is None or len(key) < histsize: |
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print(repr(key), m.trans[key]) |
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if histsize == 0: print(repr(''), m.trans['']) |
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print() |
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while True: |
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data = m.get() |
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if do_words: |
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words = data |
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else: |
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words = data.split() |
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n = 0 |
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limit = 72 |
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for w in words: |
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if n + len(w) > limit: |
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print() |
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n = 0 |
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print(w, end=' ') |
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n += len(w) + 1 |
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print() |
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print() |
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if __name__ == "__main__": |
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test() |
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