Python Program: Find Prime Numbers in Python | Detailed Examples , Multiple Approaches

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In this post we will go through the basic python program to find the prime numbers. We will also run the examples and corresponding output.

Prime Numbers

A number that can be divided by only itself and 1 is called Prime Numbers .
For example :  2,3,5,7,11

Algorithm to Find Prime numbers

First we take input from user or take  a  value .

After that store the value into a variable .

And check the variable is prime or not with using loops and conditions

And at last print the result

Approach 1 : Prime Number using Loops

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s=12 # s is a checking value is prime or not
a=2
tr=True
while a<s: # this is a loop we access all elements less than input
if s%a==0 and s!=a: # condition for prime numbers
print("not prime no. :",s)
tr=False
break # it break loop
a=a+1
if tr==True:
print("prime no.:" ,s)
Output:
not prime no. : 12
s=12 # s is a checking value is prime or not a=2 tr=True while a<s: # this is a loop we access all elements less than input if s%a==0 and s!=a: # condition for prime numbers print("not prime no. :",s) tr=False break # it break loop a=a+1 if tr==True: print("prime no.:" ,s) Output: not prime no. : 12
s=12     # s is a checking value is prime or not 
a=2
tr=True
while a<s:    # this is a loop  we access all elements less than input 
  if s%a==0 and s!=a:   # condition for prime numbers 
    print("not prime no. :",s)
    tr=False
    break   # it break loop 
  a=a+1
if tr==True:   
  print("prime no.:" ,s)

Output:
    not prime no. : 12

Approach 2:  Function to Find Prime Numbers

Now we Use functions for finding the number is prime or not  :

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def prime1(n): # function
s = True
for i in range(2,n): # loop for accessing and range for 3 t0 10
if n%i==0 : # condition
s=False
break
return s
for i in range(3,10):
n=i
print(prime1(n))
Output :
True
False
True
False
True
False
False
def prime1(n): # function s = True for i in range(2,n): # loop for accessing and range for 3 t0 10 if n%i==0 : # condition s=False break return s for i in range(3,10): n=i print(prime1(n)) Output : True False True False True False False
def prime1(n):  # function 
    s = True
    for i in range(2,n): # loop for accessing  and range for 3 t0 10
        if n%i==0 :    # condition
            s=False
            break
    return s
for i in range(3,10):  
    n=i
    print(prime1(n))

Output :
   True
   False
   True
   False
   True
   False
  False

 

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