utilities & musings

new version of my cp() function that returns a generator.

ikiel — Thu, 29 Apr 2010 18:50:50 -0700

</div>
<div>
def cp(*lists):      
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  ps = [0]*len(lists)
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<div>
  ls = [len(l) for l in lists]
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<div>
  while 1:
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    yield [l[p] for l, p in zip(lists, ps)]
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<div>
    for c in reversed(xrange(len(lists))):
</div>
<div>
      ps[c] = (ps[c]+1) % ls[c]
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      if ps[c]:
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        break
</div>
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    else:
</div>
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      return
</div>
<div>

matrix multiplier with lc

ikiel — Tue, 06 Apr 2010 18:55:34 -0700

def mm(m1, m2):
  n = len(m2)
  if not n == len(m1[0]): 
    raise ValueError("error: mismatched dimensions (width 1 must equal height 2)")
  return [[sum((m1i[k]*m2[k][j] for k in xrange(n))) for m1i in m1] for j in xrange(len(m2[0]))]

note, i think this actually might return the columns and rows transposed. i haven't checked it out.

update to my xrange()

ikiel — Sat, 13 Mar 2010 01:37:20 -0800

I made a couple of improvements to my xrange function.

def xr(start=None, end=None, increment=None, count=None):
  if start is None:
    start = 0
  if end is None: 
    end = ""
  if count is None: 
    count = ""
  if increment is None:
    if end >= "" or count >= "":
      increment = 1
    else:
      increment = (end-start)/count
  n = 0
  while n < count:
    r = start+increment*n
    if r >= end:
      break
    if r==int(r):
      r=int(r)
    n += 1
    yield r

You can run it with any combination of or none of the optional parameters. Since it's a generator, if end or count isn't defined, it'll just keep on going. increment defaults to 1, unless it can be derived from end and count. start defaults to 0. If end and count are defined, it'll go until end or count is reached - whichever comes first.

Caveat.. Don't run this like xr(100), that'll tell it to start at 100 and go up. Fixing that while still allowing xr() would be a PITA.

easy way to remember Python's precedence order.

ikiel — Sun, 28 Feb 2010 14:21:42 -0800

a good way to remember Python's order of operations:

a = lambda: b or c and not d in e is f != g == h < i | j ^ k & l << m + n * o ** p ** -q

the entire line is evaluated right-to-left.

(** is put in there twice to show that it's right-associative.)

factoring large numbers

ikiel — Fri, 26 Feb 2010 06:06:42 -0800

this program will factor numbers up to 10e19 in almost no-time

requires a file of prime numbers, the file i have is about 530MB.

##by Richard A. Nichols III, 2007
## 
##factor() returns the factorization of a given number.
## 
##primes.txt should be a newline-separated list of all prime numbers to
##an arbitrary limit.  i got my primes from
##http://primes.utm.edu/lists/small/millions/ and converted them to the above
##format.
## 
##it runs pretty fast up until numbers in the order of 10**19
 
import sys
inf = open('primes.txt','r')
primes = [int(inf.readline())]
primesset = set(primes)
 
def factor(number, factors=[], lpi=0):
  global primes, primesset
  if number in primesset:
    return factors+[number] if factors else []
  sqrt = int(number ** .5)
  pi = lpi
  prime = primes[pi]
  while prime <= sqrt:
    if pi==len(primes):
      p = inf.readline()
      if p=='' or p=='\n': raise ValueError("--Cannot factor because the prime numbers list has been exhausted--")
      prime = int(p)
      primes += [prime]
      primesset.add(prime)
    else:
      prime = primes[pi]
    if number % prime == 0:
      return factor(number/prime, factors+[prime], pi)
    pi += 1
  return factors+[number] if factors else [] 
 
 
if __name__ == "__main__":
 
 
  if len(sys.argv)==2:
    try: factors = factor(int(sys.argv[1]))
    except ValueError, e: print e
    else: print '['+', '.join(str(f) for f in factors)+']' if factors else "prime"
  else:
    for x in range(18):
      number = int('1'*(x+1))
      print
      print number
      try: factors = factor(number)
      except ValueError, e: print e
      else: print '['+', '.join(str(f) for f in factors)+']' if factors else "prime"

ex:

D:\projects\py>factor.py 0923840284985
[5, 59, 107, 1193, 24533]

running factor.py with no parameter will execute a demonstration

absrel

ikiel — Fri, 26 Feb 2010 03:22:40 -0800

i made this for a guy named eep for his philosophy of "absolute relativity". it uses Pygame.

import sys, pygame, math, random
 
size = width, height =  512, 512
minradius = 2
maxspeed = 1
minspeed = -1
#depthspeeds = [1,1,1,1,1,1,1,1,1,1]
 
#edit any of those numbers you wish.
#speeds may be negative or positive. negative is counterclockwise.
#you must have at least log height/minradius base 2 numbers in depthspeeds.
#comment out the depthspeeds line to randomize.
#maxspeed and minspeed are only used if depthspeeds are randomized.
 
depths = int(math.log(height/minradius, 2))
random.seed()
if "depthspeeds" not in globals():
  depthspeeds = [random.uniform(minspeed, maxspeed) for x in xrange(depths)]
black = 0, 0, 0
 
class circle:
  def __init__(self, angle, depth, distance):
    self.radius = height/2**depth/2
    self.depth = depth
    self.angle = angle
    self.distance = distance
    self.angleinc = math.atan2(depthspeeds[depth],distance)
    if self.depth < depths-1:
      self.child1 = circle(math.pi/2, depth+1, height/2**depth/4)
      self.child2 = circle(math.pi*1.5, depth+1, height/2**depth/4)
 
  def docircle(self, pivotx, pivoty):
    posx = pivotx+self.distance*math.cos(self.angle)
    posy = pivoty+self.distance*math.sin(self.angle)
    pygame.draw.circle(screen, (255,255,255), (posx, posy), self.radius, 1)
    self.angle += self.angleinc
    if self.depth < depths-1:
      self.child1.docircle(posx, posy)
      self.child2.docircle(posx, posy)
 
pygame.init()
screen = pygame.display.set_mode(size)
 
maincircle = circle(0, 0, 0)
 
while pygame.event.poll().type != pygame.QUIT:
  screen.fill(black)
  maincircle.docircle(width/2, height/2)
  pygame.display.flip()
 
#by Richard A. Nichols III

phonic anagrams

ikiel — Fri, 26 Feb 2010 02:50:47 -0800

shows an anagram of a given word, but works using phonems instead of letters.

requires the cmu phonic dictionary (freely downloadable). might use an old version;just replacethe version number.

 
import re
word = raw_input("ENTER YOUR WORD: ").upper()
dict = open("cmudict.0.6d","r")
while True:
  line1 = dict.readline().split()   
  if line1 == []: break
  if line1[0]==word:
    dict.seek(0)
    while True:
      line2 = dict.readline().split()
      if line2==[]: break
      if line2[0][:2]=="##": continue
      for phonemes3, phonemes5, p in (([re.sub("\d","",x) for x in line1[1:]], [re.sub("\d", "", x) for x in line2[1:]], 0), (line1[1:][:], line2[1:], 1)):
        for phoneme in phonemes5:
          if phoneme in phonemes3: phonemes3.remove(phoneme)
          else: break
        else:
          print ("\n"+line2[0], "*")[p],

results with *'s are results that have not only the same phonems, but the same phonems with the same emphasis.

ex:

ENTER YOUR WORD: littering

'TIL *
ARE(2) *
EARL
EARLE
EARLL
ENGLERT *
ER *
ERL
ERLING
ERR(2)
ERTE
EURE
IL *
ILL *
ING *
INGER *
IT *
IT'LL(2) *
IT(2) *
LING *
LINGER(2) *
LIT *
LITT *
LITTER *
LITTERING *
LUHR
LYNG *
NG(2) *
OR(2) *
TER
TIL *
TILL *
TILLER *
TILLING *
TING *
TO(2) *
UR

textshift.py

ikiel — Fri, 26 Feb 2010 02:45:21 -0800

A fun way of ciphering text

import sys
text = ' '.join(sys.argv[1:])
if not text:
  text = raw_input()
nonalphas = [(p, c) for (p, c) in enumerate(text) if not c.isalpha()]
capitals = [p for p, c in enumerate(text) if c.isupper()]
for sh in xrange(-10, 11):
  if sh:
    text3 = [c for c in text.lower() if c.isalpha()]
    text3 = text3[sh:] + text3[:sh]
    for p, c in nonalphas:
      text3.insert(p, c)
    for p in capitals:
      text3[p] = text3[p].upper()
    print ''.join(text3)

enter a sentence, and then select the cipher with the offset that looks best

ex:

D:\projects\py>textshift.py
This is the day that the Lord hath made.
Rdha th mad eth isis the Dayt hatt helo.
Dhat hm ade thi sist hed Ayth atth elor.
Hath ma det his isth eda Ytha tthe lord.
Athm ad eth isi sthe day That thel ordh.
Thma de thi sis thed ayt Hatt helo rdha.
Hmad et his ist heda yth Atth elor dhat.
Made th isi sth eday tha Tthe lord hath.
Adet hi sis the dayt hat Thel ordh athm.
Deth is ist hed ayth att Helo rdha thma.
Ethi si sth eda ytha tth Elor dhat hmad.
Hisi st hed ayt hatt hel Ordh athm adet.
Isis th eda yth atth elo Rdha thma deth.
Sist he day tha tthe lor Dhat hmad ethi.
Isth ed ayt hat thel ord Hath made this.
Sthe da yth att helo rdh Athm adet hisi.
Thed ay tha tth elor dha Thma deth isis.
Heda yt hat the lord hat Hmad ethi sist.
Eday th att hel ordh ath Made this isth.
Dayt ha tth elo rdha thm Adet hisi sthe.
Ayth at the lor dhat hma Deth isis thed.

timer

ikiel — Fri, 26 Feb 2010 02:41:06 -0800

#timer.py
 
 
import pygame, time, sys
p = map(int, ''.join(sys.argv[1:]).split(':'))
s = p.pop()
if p: s += p.pop()*60
if p: s += p.pop()*3600
time.sleep(s)
pygame.mixer.init(11025)
pygame.mixer.Sound('d:\\utils\\ringin.wav').play(1)
time.sleep(10)

and a batch file that goes..

@echo off
@echo current time is %TIME%
start d:\python26\pythonw \utils\timer.py %*

example:

D:\>timer 4:00
current time is 5:41:52.74
D:\>timer 4
current time is 5:41:56.07
D:\>timer 4:10:00
current time is 5:42:05.34

calculator

ikiel — Fri, 26 Feb 2010 02:32:28 -0800

from __future__ import division
import sys
from math import *
print eval(' '.join(sys.argv[1:]))

and then i have a batch file that goes:

@echo off
if "%1"=="" goto calc
d:\python26\python d:\utils\calc.py %*
goto end
:calc
calc.exe
:end

ex:

C:\>calc 12*sin(1)
10.0976518177

C:\>