python list prime numbers behind n code example

Example 1: python calculate prime numbers until numer

until = 20
[n for n in range(2, until) if all(n % m != 0 for m in range(2, n-1))]

Example 2: first n prime number finder in python

>>> def getprimes(x):	primes = []	# Loop through 9999 possible prime numbers	for a in range(1, 10000):		# Loop through every number it could divide by		for b in range(2, a):			# Does b divide evenly into a ?			if a % b == 0:				break		# Loop exited without breaking ? (It is prime)		else:			# Add the prime number to our list			primes.append(a)		# We have enough to stop ?		if len(primes) == x:			return primes		>>> getprimes(5)[1, 2, 3, 5, 7]>>> getprimes(7)[1, 2, 3, 5, 7, 11, 13]