Help Editing/Problem with outputs

[stanthaman42]

Hello there. I am Currently working on a program that produces every number (1000-9999) and their prime permutations(single, double, triple, and quadruple digit numbers). When I print my output, it is telling me that 1000 has 2 prime permutations which is incorrect. Can anyone see if I made a mistake with my coding that might be easy to fix or what could be the cause of the wrong data?

Thanks, the code is posted below:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68

import math   def getAllCombinations(s, length):     if length == 0:         return ['']     else:         ret = []         for idx, c in enumerate(s):             combos = getAllCombinations(s[0:idx] + s[idx+1:], length - 1)             for i in range(len(combos)):                 combos[i] = c + combos[i]             ret += combos         return ret   def getPermutations(s, ret, swapIdx = 0):     if swapIdx == len(s):         ret.append(int(''.join(s)))       for i in range(swapIdx, len(s)):         cpy = [c for c in s]         cpy[swapIdx], cpy[i] = cpy[i], cpy[swapIdx]         getPermutations(cpy, ret, swapIdx + 1)   def getAllPermutations(i):     s = str(i)     allPerms = set()     for i in range(len(s)):         curCombos = getAllCombinations(s, i + 1)         for combo in curCombos:             ret = []             getPermutations(combo, ret)             allPerms = allPerms.union(set(ret))     return list(allPerms)   def isPrime(n):     for i in range(2, math.ceil(n**(1/2)) + 1):         if n % i == 0:             return False     return True   def getNumPrimes(i):     perms = getAllPermutations(i)     numprimes = 0     for perm in perms:         if (isPrime(perm)):             numprimes += 1     return numprimes     def find_maxPrimes():     max = 0     maxNum = 0     for i in range (1000, 10000):         cur = getNumPrimes(i)         if (max < cur):             max = cur             maxNum = i     return maxNum   print(find_maxPrimes())   def find_maxPrimes2(): #    max = 0 #    maxNum = 0 #Printing here directly     for i in range (1000, 10000):         print(i, " ---> ", getNumPrimes(i))       find_maxPrimes2()

Output:
1000   --->   2
1001   --->   4
1002   --->   2
1003   --->   7
1004   --->   5
1005   --->   3
1006   --->   4
1007   --->   8
1008   --->   2
1009   --->   6
1010   --->   4

[ichabod801]

isPrime is counting 0 and 1 as prime. Neither are prime.

[stanthaman42]

isPrime is counting 0 and 1 as prime. Neither are prime.

What Is the best way to fix that without causing issues with other aspects of the data?

[ichabod801]

You could add:

1 2	if i < 2:     return False

However, note that you are checking the same numbers over and over again to see whether they are prime. I would instead find all the primes up to 10000 and put them in a set. Then you can just check each number to see if it is in the set.

Also, you call find_maxPrimes (which gets the maximum getNumPrimes) and find_maxPrimes2 (which prints all the getNumPrimes), so you are calculating all of the getNumPrimes twice. If you just added the print statement from find_maxPrimes2 to find_maxPrimes, you do it all at the same time.

[stanthaman42]

You could add:

1 2	if i < 2:     return False

However, note that you are checking the same numbers over and over again to see whether they are prime. I would instead find all the primes up to 10000 and put them in a set. Then you can just check each number to see if it is in the set.

Also, you call find_maxPrimes (which gets the maximum getNumPrimes) and find_maxPrimes2 (which prints all the getNumPrimes), so you are calculating all of the getNumPrimes twice. If you just added the print statement from find_maxPrimes2 to find_maxPrimes, you do it all at the same time.

What line would be be best to add the "if i<2:return False"?


Also, I am able to store the number of primes up to 100000 labeled p, but what would be the simplest way to transfer the program i have to check inside of the array p?

[ichabod801]

The if clause should go after line 35.

If you have the primes in a list p that is a global variable, you can just do:

1 2	def isPrime(i):     return i in p

Note that if p is a set it will be faster than if p is a list. The set can use a hash lookup, while the list has to check each item in turn.

[stanthaman42]

The if clause should go after line 35.

If you have the primes in a list p that is a global variable, you can just do:

1 2	def isPrime(i):     return i in p

Note that if p is a set it will be faster than if p is a list. The set can use a hash lookup, while the list has to check each item in turn.

Thank you very much!

Also, what is the best way to get the outputs into a .txt file or into a excel file?

[ichabod801]

There is a files tutorial in the tutorials sub-forum, check that out.

If you save each line with the values separated by commas and give it a .csv extension, it will load right into excel when you double click on it.