Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Tip revision: 2bd31b5fde32194a63ca1e782e2578c6bd2ba759 authored by Ćukasz Langa on 16 September 2020, 21:23:13 UTC
Python 3.9.0rc2
Python 3.9.0rc2
Tip revision: 2bd31b5
markov.py
#!/usr/bin/env python3
"""
Markov chain simulation of words or characters.
"""
class Markov:
def __init__(self, histsize, choice):
self.histsize = histsize
self.choice = choice
self.trans = {}
def add(self, state, next):
self.trans.setdefault(state, []).append(next)
def put(self, seq):
n = self.histsize
add = self.add
add(None, seq[:0])
for i in range(len(seq)):
add(seq[max(0, i-n):i], seq[i:i+1])
add(seq[len(seq)-n:], None)
def get(self):
choice = self.choice
trans = self.trans
n = self.histsize
seq = choice(trans[None])
while True:
subseq = seq[max(0, len(seq)-n):]
options = trans[subseq]
next = choice(options)
if not next:
break
seq += next
return seq
def test():
import sys, random, getopt
args = sys.argv[1:]
try:
opts, args = getopt.getopt(args, '0123456789cdwq')
except getopt.error:
print('Usage: %s [-#] [-cddqw] [file] ...' % sys.argv[0])
print('Options:')
print('-#: 1-digit history size (default 2)')
print('-c: characters (default)')
print('-w: words')
print('-d: more debugging output')
print('-q: no debugging output')
print('Input files (default stdin) are split in paragraphs')
print('separated blank lines and each paragraph is split')
print('in words by whitespace, then reconcatenated with')
print('exactly one space separating words.')
print('Output consists of paragraphs separated by blank')
print('lines, where lines are no longer than 72 characters.')
sys.exit(2)
histsize = 2
do_words = False
debug = 1
for o, a in opts:
if '-0' <= o <= '-9': histsize = int(o[1:])
if o == '-c': do_words = False
if o == '-d': debug += 1
if o == '-q': debug = 0
if o == '-w': do_words = True
if not args:
args = ['-']
m = Markov(histsize, random.choice)
try:
for filename in args:
if filename == '-':
f = sys.stdin
if f.isatty():
print('Sorry, need stdin from file')
continue
else:
f = open(filename, 'r')
with f:
if debug: print('processing', filename, '...')
text = f.read()
paralist = text.split('\n\n')
for para in paralist:
if debug > 1: print('feeding ...')
words = para.split()
if words:
if do_words:
data = tuple(words)
else:
data = ' '.join(words)
m.put(data)
except KeyboardInterrupt:
print('Interrupted -- continue with data read so far')
if not m.trans:
print('No valid input files')
return
if debug: print('done.')
if debug > 1:
for key in m.trans.keys():
if key is None or len(key) < histsize:
print(repr(key), m.trans[key])
if histsize == 0: print(repr(''), m.trans[''])
print()
while True:
data = m.get()
if do_words:
words = data
else:
words = data.split()
n = 0
limit = 72
for w in words:
if n + len(w) > limit:
print()
n = 0
print(w, end=' ')
n += len(w) + 1
print()
print()
if __name__ == "__main__":
test()