CODEWITHSUNDEEP
python
Nazaal
Nazaal

Reputation: 447

Project Euler #10 Python

I'm a newbie attempting ProjectEuler problems.

Problem #10 is as follows: Find the sum of all the primes below two million.

My code is as follows

a=1
s=0
p=[]                                                         #just wanna see the primes for myself so creating a list for that       
while a<2000000:                                            #while value of primes is less than 2million
        if all(a%i!=0 for i in range(3,int(a**0.5)+1)):     #checks if the number is prime
            s=s+a                                           #add primes to the sum
            p.append(a)                                     #add the primes to their list
        a=a+2                                               #so that we only test odd numbers
print(s)
print(p)

So the problem is, the number 1 pops up in the list, and 2 doesn't show up. All other prime numbers get included. I tried many tweaks to find the sum and list of primes below 10 but the problem persists. What am I doing wrong?

Upvotes: 0

Views: 274

Answers (2)

trans1st0r
trans1st0r

Reputation: 2073

Start with a=5, ignoring the first 2 primes 2 and 3.

and s = 5 (adding up the first 2 primes, 2 and 3)

Loop from 5 to 2 million.

The a = a+2 line will hold starting from a = 5.

Upvotes: 0

BlackBear
BlackBear

Reputation: 22979

You are skipping 2 altogether, because you start from a=1 and a=a+2 in the first iteration

Upvotes: 1

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