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Updated 3 years ago

## Python Challenging questions

Alphabetic patterns

Description

Given a positive integer 'n' less than or equal to 26, you are required to print the below pattern

Sample Input: 5

Sample Output :

--------e--------

------e-d-e------

----e-d-c-d-e----

--e-d-c-b-c-d-e--

e-d-c-b-a-b-c-d-e

--e-d-c-b-c-d-e--

----e-d-c-d-e----

------e-d-e------

--------e--------

```
n=5
alpha="abcdefghijklmnopqrstuvwxyz"
s=""
l=[]
for i in range(n):
s="-".join(alpha[i:n])
l.append(s[::-1]+s[1:])
length=len(l[0])
for i in range(n-1,0,-1):
print(l[i].center(length,"-"))
for i in range(n):
print(l[i].center(length,"-"))
```

```
--------e--------
------e-d-e------
----e-d-c-d-e----
--e-d-c-b-c-d-e--
e-d-c-b-a-b-c-d-e
--e-d-c-b-c-d-e--
----e-d-c-d-e----
------e-d-e------
--------e--------
```

Sum of Primes

Description

Write python code to find the sum of prime numbers from 2 to n where n is a positive integer entered by the user.

Note: n can be non-prime or prime. You have to find sum of primes till n and not sum of n prime numbers. i.e. for input 10, output should be 17.

```
num=12 #int(input())
def primen(n):
f=0
for i in range(2,n):
if n%i==0:
f=f+1
return(f)
count=0
for i in range(2,num+1):
if primen(i) ==0:
count=count+i
print(count)
## write a function to find if prime or not, then call that and add if prime
```

```
28
```