I have a program that is supposed to ask how many primes to calculate then write them all to a text file. However, it creates the file then dosen't run.
def constantcall():
j = 2
chk = 1
f = open("primes.txt", "w")
primes = []
notprimes = []
ask = input("how many primes? ")
while len(primes) < int(ask):
k = 2
while not(k==j) and not(j%k==0):
k = k + 1
if k == j:
primes.append(j)
f.write(str(j)+"\n")
else:
notprimes.append(j)
if len(primes) >= 1000*chk:
chk = chk + 1
print("There have been " + str(len(primes)) + " primes counted so far")
j = j + 1
print("Primes written to file 'primes.txt', " + str(len(primes)) + " written")
f.close
return(" ")
if __name__ == '__main__':
while(True):
constantcall()
Your problem is the code:
while len(primes) < int(ask):
k = 2
at this point len(primes) is less than int(ask), and there is nothing that add items to primes, so infinite loop.
Your code must be (in order to avoid infinite loop):
def constantcall():
j = 2
chk = 1
f = open("primes.txt", "w")
primes = []
notprimes = []
ask = input("how many primes? ")
while len(primes) < int(ask):
k = 2
while not(k==j) and not(j%k==0):
k = k + 1
if k == j:
primes.append(j)
f.write(str(j)+"\n")
else:
notprimes.append(j)
if len(primes) >= 1000*chk:
chk = chk + 1
print("There have been " + str(len(primes)) + " primes counted so far")
j = j + 1
print("Primes written to file 'primes.txt', " + str(len(primes)) + " written")
f.close
return(" ")
if __name__ == '__main__':
constantcall()
Using Sieve of Eratosthenes algorithm
You could use the algorithm Sieve of Eratosthenes:
def primes(count):
"""
Returns a list with the first `count` prime numbers.
An advice: If you will be using this functiona a lot it's better
for performance if you precalculate cribe.
"""
# Calculate primes up to 50, you can change this to your preference.
MAX = 50
sieve = [1] * MAX
for i in range(2, int(MAX ** 0.5) + 2 ):
for j in range(i + i, MAX, i):
sieve[j] = 0
# Finally primes are indexes in the list that still has 0.
result = []
for index, elem in enumerate(sieve):
if elem == 1: result.append(index)
return result[1:count + 1]
Your code can then be rewrited as:
def constantcall():
f = open("primes.txt", "w")
ask = int(input("how many primes? "))
prime_numbers = primes(ask)
f.writelines(map(lambda x: "{0}\n".format(x), prime_numbers))
if __name__ == '__main__':
constantcall()
Your code does nothing.
while len(primes) < int(ask):
k = 2
Is useless.
while not(k==j) and not(j%k==0):
k = k + 1
Is useless as j is always 2.
if k == j:
primes.append(j)
f.write(str(j)+"\n")
else:
notprimes.append(j)
Here you append 2 to primes once.
if len(primes) >= 1000*chk:
chk = chk + 1
print("There have been " + str(len(primes)) + " primes counted so far")
j = j + 1
print("Primes written to file 'primes.txt', " + str(len(primes)) + " written")
f.close()
return
So len(primes) is always 1.
Here is a solution. Sorry for C language, but you could easily pythonize it.
#include <stdio.h>
typedef unsigned long long ull;
int main(){
ull numb=10000,stop=20000;
ull i,c;
int cnt;
printf("Here are the primes between %lld and %lld :\n\n",numb,stop);
while(numb<=stop){
for(i=1;i<=numb;++i){
if(!(numb%i)) ++cnt;
}
if ((cnt==2) || (i==1)) printf("%lld; ",numb);
cnt=0;
++numb;
}
printf("\n\nThat's all\n");
}
Related
Why does my program keep consuming memory and never release it? If you try to run it, you will know what I mean.
#!/usr/local/bin/env python
def is_prime(num):
if num <= 1: return False
if num != 2 and num % 2 == 0: return False
to = num / 2 + 1
for x in range(3, to, 2):
if num % x == 0: return False
return True
if __name__ == "__main__":
primes = []
for x in range(2, 100):
if is_prime(x): primes.append(x)
print(primes)
product = primes[0]
for i in range(1, len(primes)):
print("prime: " + str(primes[i]))
new_prime = product * primes[i] + 1
if is_prime(new_prime):
print("new prime: " + str(new_prime))
else:
print(str(new_prime) + " is not prime! [error]")
product *= primes[i]
It turns out that python2 has memory leak. Python3 won't have this issue.
Write a program that prints the numbers in the given range. But for multiples of three print "Fizz" instead of the number and for the multiples of five print "Buzz".For numbers which are multiples of both three and five print "FizzBuzz". Print a new line after each string or number.
Input Format:- First line will be the number of testcase, T. Next line will have T integers, denoted by N.
Out Format:- For each testcase, print the number from 1 to N. But follow the rules given in the problem statement.
SAMPLE INPUT 1
2
3 15
This is my code:-
n_input = int(input())
x, y = map(int, input().split(" "))
for i in range(1, x + 1):
if i % 3 == 0 and i % 5 == 0:
print("FizzBuzz", sep="\n")
elif i % 3 == 0:
print("Fizz", sep="\n")
elif i % 5 == 0:
print("Buzz", sep="\n")
else:
print(i, sep="\n")
for i in range(1, y+1):
if i % 3 == 0 and i % 5 == 0:
print("FizzBuzz", sep="\n")
elif i % 3 == 0:
print("Fizz", sep="\n")
elif i % 5 == 0:
print("Buzz", sep="\n")
else:
print(i, sep="\n")
I know my mistake that i have to print according to initial input but i don't know how to fix it.
Thank you
k = int(input()) # useless given what we're doing below
cases = [int(i) for i in input().split()]
for case in cases:
for k in range(1, case + 1):
out = ""
if (k % 3) == 0:
out += "fizz"
if (k % 5) == 0:
out += "buzz"
if out != "":
print(out)
else:
print(k)
The second line is shorthand for
cases = []
for i in input().split():
cases.append(int(i))
Run my Colab notebook
Answer in C#:
A first line is a number of case.
The second line is a value.
Example :
Line1: 3
Line2: 10,55,20
Example 2:
Line1: 4
Line2: 10,55,20, 44
Code:
using System;
class sasikumarv{
public static void Main()
{
var read = Console.ReadLine();
int T= Convert.ToInt32(read);
var line = Console.ReadLine();
var numbers = line.Split(' ');
if(first>=1 && first<=10)
{
for(int cnt=0;cnt<T;cnt++)
{
for(int i = 1; i <= Convert.ToInt32(numbers[cnt]); i++)
{
if (i % 15 == 0)
Console.WriteLine("FizzBuzz" + " ");
else if (i % 3 == 0)
Console.WriteLine("Fizz" + " ");
else if (i % 5 == 0)
Console.WriteLine("Buzz" + " ");
else
Console.WriteLine(i + " ");
}
}
}
}
}
Here's my code:
def ispalindrome(p):
temp = p
rev = 0
while temp != 0:
rev = (rev * 10) + (temp % 10)
temp = temp // 10
if num == rev:
return True
else:
return False
num = int(input("Enter a number: "))
i = 1
count = 0
sum = 0
while (count <= num - 1):
if (palindrome(i) == True):
sum = sum + i
count = count + 1
i = i + 1
print("Sum of first", num, "palindromes is", sum)
I believe my ispalindrome() function works. I'm trying to figure out what's wrong inside my while loop.
here's my output so far:
n = 1 answer = 1,
n = 2 answer = 22,
n = 3 answer = 333 ...
I also think the runtime on this really sucks
Please help
i belive the problem is with your ispalindrom functon it returns 200 as palindrome number
def ispalindrome(p):
rev = int(str(p)[::-1])
if p == rev:
return True
else:
return False
num = int(input("Enter a number: "))
i = 1
count = 0
sum = 0
while (count <= num - 1):
if (ispalindrome(i) == True):
print(i)
sum = sum + i
count = count + 1
i = i + 1
print("Sum of first", num, "palindromes is", sum)
def is_palindrome(number):
return str(number) == str(number)[::-1]
num = int(input("Enter a number: "))
palindromes = [i for i in range(1, num) if is_palindrome(i)]
print(f"Sum of the {len(palindromes)} palindromes in range {num} is {sum(palindromes)}")
MyFunctions file file -
def factList(p,n1):
counter = 1
while counter <= n1:
if n1 % counter == 0:
p.append(counter)
counter = counter + 1
def isPrime(lst1,nbr):
factList(lst1, nbr)
if len(lst1) == 2:
return True
else:
return False
def nextPrime(nbr1):
cnt1 = 1
while cnt1 == 1:
nbr1 == nbr1 + 1
if isPrime(lst2,nbr1):
cnt1 = 0
Filetester file -
nbr1 = 13
nextPrime(nbr1)
print nbr1
My isPrime function already works I'm tring to use my isPrime function for my nextPrime function, when I run this I get
">>>
13
" (when using 13)
">>> " (When using 14)
I am supposed to get 17 not 13. And if I change it to a composite number in function tester it gets back in a infinite loop. Please only use simple functions (the ones I have used in my code).
This is NOT the right way to do this, but this is the closest adaptation of your code that I could do:
def list_factors_pythonic(number):
"""For a given number, return a list of factors."""
factors = []
for x in range(1, number + 1):
if number % x == 0:
factors.append(x)
return factors
def list_factors(number):
"""Alternate list_factors implementation."""
factors = []
counter = 1
while counter <= number:
if number % counter == 0:
factors.append(counter)
return factors
def is_prime(number):
"""Return true if the number is a prime, else false."""
return len(list_factors(number)) == 2
def next_prime(number):
"""Return the next prime."""
next_number = number + 1
while not is_prime(next_number):
next_number += 1
return next_number
This would be helpful:
def nextPrime(number):
for i in range(2,number):
if number%i == 0:
return False
sqr=i*i
if sqr>number:
break
return True
number = int(input("Enter the num: ")) + 1
while(True):
res=nextPrime(number)
if res:
print("The next number number is: ",number)
break
number += 1
I don't know python but if it's anything like C then you are not assigning anything to your variables, merely testing for equality.
while cnt1 == 1:
nbr1 == nbr1 + 1
if isPrime(lst2,nbr1):
cnt1 == cnt1 + 1
Should become
while cnt1 == 1:
nbr1 = nbr1 + 1 << changed here
if isPrime(lst2,nbr1):
cnt1 = cnt1 + 1 << and here
Well this code help you
n=int(input())
p=n+1
while(p>n):
c=0
for i in range(2,p):
if(p%i==0):
break
else:c+=1
if(c>=p-2):
print(p)
break
p+=1
this code optimized for finding sudden next prime number of a given number.it takes about 6.750761032104492 seconds
def k(x):
return pow(2,x-1,x)==1
n=int(input())+1
while(1):
if k(n)==True:
print(n)
break
n=n+1
I am making some practice code for a game similar to the board game, MasterMind-- and It keeps coming out with this error, and I can't figure out why it's doin it. Here's the code:
def Guess_Almost (Guess, Answer):
a = ''.join([str(v) for v in Answer])
g = str(Guess)
n = 0
am = 0
while n < 5:
if g[n] == a[0]:
am = am + 1
if g[n] == a[2]:
am = am + 1
if g[n] == a[3]:
am = am + 1
if g[n] == a[3]:
am = am + 1
n = n + 1
return(am)
Okay, the Guess is specified to be 4 integers, and the Answer is a list containing 4 numbers. They both have the same 'len' after the code, so i don't have a clue.
The point of this code is to turn the Answer into a string of 4 numbers, and see if any of those numbers match thoise of the guess, and return how many total matches there are.
See if this helps
def Guess_Almost (Guess, Answer):
a = ''.join([str(v) for v in Answer])
g = str(Guess)
n = 0
am = 0
if len(g) >= 5 and len(a) >=4:
while n < 5:
if g[n] == a[0]:
am = am + 1
if g[n] == a[2]:
am = am + 1
if g[n] == a[3]:
am = am + 1
if g[n] == a[3]:
am = am + 1
n = n + 1
return(am)