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.

In the loop and if block is used that uses "isalpha" string method, which checks the check alphabetic character in the given value. if this is true it will calculate all value in "val" variable and return its value.     At the last, the print method is used, which calls the lettersOnly method and prints its return value.

Ireally like network models.

Through the process of sedimentation,sediment is turned back to rock to form sedimentation.the process of sedimentation is: > deposition-where fragments were deposited into the river or sea under gravity or travelling agent such as wind or water. > sedimentation-the fragments deposited in the river sedimented and accumulate> compaction-the layers of fragments deposited undergoes compaction due to the weight if the upper layers> cementation-chemical substance of the fragments such as cement dissolved into the water and cement the other fragments together to form sedimentary rock.thus,cementation and compaction are the process.on the other hand, transformation only occur when a rock under goes metamorphism(compaction or extreme heat).while recrystillization occurs when a rock is melted and cooled down,which also requires metamorphism to take place.hope it !