10 examples of 'print n prime numbers in python' in Python

20
def prime(num):
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    # num is actually a string because input() returns strings. We'll convert it to int
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    num = int(num)
23
24
    if num < 0:
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        print("Negative integers can not be prime")
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        quit()
27
    if num is 1:
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        print("1 is neither prime nor composite")
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        # See how I lazily terminated program otherwise it'd forward "None"(default behaviour of python when function
30
        # returns nothing) rather than True or False. Which could mess up the program.
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        # If we hit this if statement above statement is printed then program exits.
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        quit()  # Now you don't need to get sys.exit() to exit python has quit to handle the same thing
33
    if num in [2, 3]:
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        # if given argument is 2 or 3, it is prime. We used list without defining a variable which is perfectly valid
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        return True
36
    if num % 2 == 0:  # excluding all even numbers except two.
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        return False
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    else:
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        # Here we are starting counter variable from 3 in range. Second argument excludes numbers above one third
40
        # of the given argument. Third argument in range sets steps to take to 2. This makes loop to iterate odds
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        for x in range(3, int(num/3), 2):
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            # Checking if argument is divisible by counter. % is modulus operator which returns remainder of division
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            if num % x == 0:
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                return False
45
    # It's okay to have more than one return statement when program hits return statement it exits the function.
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    return True

746
def prime_number_factorisation(n):
747
    if n < 2:
748
        return [n]
749
    i = 2
750
    factors = []
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    while i * i <= n:
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        if n % i:
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            i += 1
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        else:
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            n //= i
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            factors.append(i)
757
    if n > 1:
758
        factors.append(n)
759
    return factors

16
def primeGen(n):
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    for i in xrange(2, n):
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        prime = True
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        if i % 2 == 0 and i != 2:
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            continue
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        sqrtp = int(i ** 1 / 2)
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        for j in xrange(2, sqrtp):
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            if j % 2 == 0:
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                continue
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            if i % j == 0:
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                prime = False
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                break
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        if prime:
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            yield i

12
def primes():
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    yield 2
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    yield 3
15
16
    for i in itertools.count(start=5, step=2):
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        if is_prime(i):
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            yield i

1
def is_prime(n):
2
	if n < 2:
3
		return False
4
5
	i = 2
6
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	while i * i <= n:
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		if n % i == 0:
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			return False
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		i += 1
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13
	return True

3
def is_prime(n):
4
    i = 3
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    while i * i <= n:
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        if n % i == 0: return False
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        i += 2
8
    return True

1285
def primefactors(n, limit=None, verbose=False):
1286
    """Return a sorted list of n's prime factors, ignoring multiplicity
1287
    and any composite factor that remains if the limit was set too low
1288
    for complete factorization. Unlike factorint(), primefactors() does
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    not return -1 or 0.
1290
1291
    Examples
1292
    ========
1293
1294
    >>> from sympy.ntheory import primefactors, factorint, isprime
1295
    >>> primefactors(6)
1296
    [2, 3]
1297
    >>> primefactors(-5)
1298
    [5]
1299
1300
    >>> sorted(factorint(123456).items())
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    [(2, 6), (3, 1), (643, 1)]
1302
    >>> primefactors(123456)
1303
    [2, 3, 643]
1304
1305
    >>> sorted(factorint(10000000001, limit=200).items())
1306
    [(101, 1), (99009901, 1)]
1307
    >>> isprime(99009901)
1308
    False
1309
    >>> primefactors(10000000001, limit=300)
1310
    [101]
1311
1312
    See Also
1313
    ========
1314
1315
    divisors
1316
    """
1317
    n = int(n)
1318
    factors = sorted(factorint(n, limit=limit, verbose=verbose).keys())
1319
    s = [f for f in factors[:-1:] if f not in [-1, 0, 1]]
1320
    if factors and isprime(factors[-1]):
1321
        s += [factors[-1]]
1322
    return s

3
def is_prime(n):
4
    if n <= 1:
5
        return False
6
    elif n == 2:
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        return True
8
    elif n % 2 == 0:
9
        return False
10
    for i in xrange(3, int(sqrt(n))+1, 2):
11
        if n % i == 0:
12
            return False
13
    return True

21
def is_prime(n):
22
    for i in xrange(2, int(sqrt(n)) + 1):
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        if n % i == 0:
24
            return False
25
26
    return True

6
def is_prime(n):
7
   '''
8
   checks if a number is prime
9
   '''
10
   if n < 2:
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      return False
12
   if n == 2:
13
      return True
14
   for x in range(2, int(n**0.5)+1, 2):
15
      if n % x == 0:
16
         return False
17
   return True