a better prime number generator

[Alves, Carlos Alberto - Coelce]

Why not try a variation from basic example in Python Tutorial by Guido van
Rossum?!

def getPrimesTill(x):
	primes=[2]
	for i in range(3,x,2):
		for x in range(2,i):
			if i%x==0:
				break
		else:
			primes.append(i)
	return primes

Carlos Alberto
COELCE/DPRON-Departamento de Projetos e Obras Norte
Fone: 677- 2228
e-mail: calves at coelce.com.br
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-----Original Message-----
From: dhillon_rs at rediffmail.com [mailto:dhillon_rs at rediffmail.com]
Sent: Sunday, October 21, 2001 2:40 PM
To: python-list at python.org
Subject: a better prime number generator


hi all,
I have just been introduced to pyton and find it a very good ( takes
off all the bookwork ) language. I was trying to develope a ast prime
number generator. I designed the following algo. Can you please
suggest a faster one or modifications to this only to make it faster

#the following algo returns all the primes below x

def getPrimesTill(x):
	a = range(2,x)
	c = [2]
	
	i = 0
	j = 0

	foundone = 1
	
	while i < len(a):
		while j < len(c) and (c[j] < (.5 * a[i]) ) and foundone ==
1:
			if a[i]%c[j] == 0:
				foundone = 0
			j = j + 1
		if foundone == 1 and i > 0:
			c.append(a[i])
		j = 0
		foundone = 1
		i = i + 1
	return c


roop
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