List comprehension and ord() in Python to remove all characters other than alphabets

Given a string consisting of alphabets and other characters, remove all the characters other than alphabets and print the string so formed. Examples:

Input : str = "$Gee*k;s..fo, r'Ge^eks?"
Output : GeeksforGeeks

This problem has existing solution please refer Remove all characters other than alphabets from string link. We will solve this problem in python quickly using List Comprehension. Approach : is

1. Traverse string 
2. Select characters which lie in range of [a-z] or [A-Z]
3. Print them together

How does ord() and range() function works in python ?

• The ord() method returns an integer representing the Unicode code point of the given Unicode character.For example,

 ord('5') = 53 and ord('A') = 65 and ord('$') = 36

• The range(a,b,step) function generates a list of elements which ranges from a inclusive to b exclusive with increment/decrement of given step.

Python3

# Python code to remove all characters
# other than alphabets from string

def removeAll(input):

    # Traverse complete string and separate
    # all characters which lies between [a-z] or [A-Z]
    sepChars = [char for char in input if
ord(char) in range(ord('a'),ord('z')+1,1) or ord(char) in
range(ord('A'),ord('Z')+1,1)]

    # join all separated characters
    # and print them together
    return ''.join(sepChars)

# Driver program
if __name__ == "__main__":
    input = "$Gee*k;s..fo, r'Ge^eks?"
    print (removeAll(input))

Output:

GeeksforGeeks

Python3

# code
string = "$Gee*k;s..fo, r'Ge^eks?"
print("".join(filter(lambda x : x.isalpha(),string)))