Write the function lettersOnly(s) that takes in a string called s, and returns a string containing only the alphabetic characters of s.

The program to this question as follows:

Program:

def lettersOnly(s): #defining method lettersOnly

   val="" #defining string variable that return value

   for i in s: #defining loop to calculate value

       if(i.isalpha()): #check condition that value is string

           val=val+ i #add value

   return val #return value

print(lettersOnly("data3base_ro1c3k5s")) #call method and print value

Output:

databaserocks

Explanation:

In the above python code, a method lettersOnly is declared that accepts a string variable  "s" in its parameter. Inside the method, a string variable "val", and loop is declared, in which the "val" variable holds method return value.