# Task
 Given a string `str`, reverse it omitting all non-alphabetic characters.

# Example

 For `str = "krishan"`, the output should be `"nahsirk"`.
 
 For `str = "ultr53o?n"`, the output should be `"nortlu"`.
 
# Input/Output


 - `[input]` string `str`

  A string consists of lowercase latin letters, digits and symbols.

 
 - `[output]` a string

Difficulty: introductory

Starter code:

def reverse_letter(string):
	

Solutions:
def reverse_letter(s):
  return ''.join([i for i in s if i.isalpha()])[::-1]



reverse_letter = lambda s: ''.join([i for i in s if i.isalpha()])[::-1]


def reverse_letter(string):
    return ''.join(filter(str.isalpha, reversed(string)))

import re
def reverse_letter(string):
    return re.sub("[^a-zA-Z]","",string)[::-1]



def reverse_letter(string):
    return ''.join(c for c in string[::-1] if c.isalpha())



def reverse_letter(s):
    return ''.join(filter(str.isalpha, s))[::-1]

reverse_letter = lambda s:''.join(reversed([x for x in s if x.isalpha()]))

def reverse_letter(string):
    result = ''
    
    for char in string:
        if char.islower():
            result = char + result
    
    return result

def reverse_letter(string):
    return "".join(c for c in string[-1::-1] if c.isalpha())

def reverse_letter(string):
    return"".join(i for i in string[::-1] if i.isalpha())



def reverse_letter(string):
    str = ""
    for n in string:
        if n.isalpha():
            str = n + str
    return str


import re
def reverse_letter(string):
    return "".join(re.findall(r"[A-Za-z]",string)[::-1])

def reverse_letter(s):
    return ''.join([i for i in s[::-1] if i.isalpha()])



def reverse_letter(string):
    new_string = ''
    alphabet = 'abcdefghijklmnopqrstuvwxyz'
    for i in string:
        if i in alphabet:
            new_string += i
    return new_string[::-1]
        



import string
def reverse_letter(string):
    
    return "".join(filter(str.isalpha,string))[::-1]



def reverse_letter(string):
    a = []
    for i in string:
        if i.isalpha():
            a.append(i)
            
    return "".join(list(reversed(a)))

def reverse_letter(string):
    rev= string[::-1]
    return "".join([x for x in rev if (x if x.isalpha() else None)])


reverse_letter=lambda s:''.join(filter(str.isalpha,s[::-1]))

def reverse_letter(string):
    return ''.join(char for char in string[::-1] if char.isalpha())



import string
def reverse_letter(s):
    return ''.join(reversed([a for a in s if a in string.ascii_letters]))



def reverse_letter(string):
    #do your magic here
    return ''.join(s for s in reversed(string) if s.isalpha())


def reverse_letter(string):
    revstr = string[::-1]
    return "".join([x for x in list(revstr) if x.isalpha()])



def reverse_letter(string):
    return ''.join(c for c in string if c.isalpha())[::-1]



reverse_letter = lambda string: ''.join([i for i in string if i.isalpha()])[::-1]

reverse_letter = lambda s: ''.join(c for c in reversed(s) if c.isalpha())



import array
def reverse_letter(string):
    a = array.array('u', string)
    a.reverse()
    return ''.join(filter(lambda x: x.isalpha(), a))

import re

def reverse_letter(string):
    return re.sub(r"[^a-z]", "", string[::-1])

def reverse_letter(string):
    string=str().join(list(filter(str.isalpha, string)))
    return string[::-1]
    #do your magic here



def reverse_letter(string):
  return ''.join(x for x in reversed(string) if x.isalpha())



reverse_letter = lambda s: ''.join(filter(lambda x: x.isalpha(), s))[::-1]

def reverse_letter(string):
    return ''.join(x for x in string[::-1] if x.isalpha())



reverse_letter=lambda s: "".join(l for l in s if l.isalpha())[::-1]

def reverse_letter(string):
    txt = ""
    for a in string:
        if a.isalpha():
            txt = txt + a
    return txt[::-1]



def reverse_letter(string):
    array = list(filter(str.isalpha, string))
    new_list = ''.join(array)
    return new_list[::-1]



def reverse_letter(string):
    string = string[::-1]
    string2=""
    for x in range(0,len(string)):
        if(string[x].isalpha()):
            string2+=string[x]
            
    return string2



import re
def reverse_letter(st):
    newst = st[::-1]
    itog = ""
    for i in newst:
        if i.isalpha():
            itog += i
    return (itog)

        


def reverse_letter(string):
    result = [i for i in string if i.isalpha()]
    return ''.join(result[::-1]) 

    
# condition must be alphabetic


import string

def reverse_letter(str):
    chars = string.ascii_lowercase
    return ''.join(i for i in str[::-1] if i in chars)    

def reverse_letter(string):
    alphabet = 'abcdefghijklmnopqrstuvwxyz'
    newString = ''
    for letter in string:
        if letter in alphabet:
            newString += letter
        else:
            continue
    return newString[::-1]



def reverse_letter(string):
    #do your magic here
    word = []
    for i in string:
        if i.isalpha() == True:
            word.append(i)
    
    word = reversed(word)
    
    word_rev = "".join(word)

    return word_rev

def reverse_letter(string):
    chars_only = ''
    
    for item in string:
        if item.isalpha():
            chars_only += item
    return chars_only[::-1] 



def reverse_letter(string):
    return ''.join([i if i.isalpha() else "" for i in reversed(string)])


def reverse_letter(string):
    a = []
    a[:] = string
    a.reverse()
    b = []
    c = ''
    let = ['a', 'b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
    for s in a:
        if s in let:
            b.append(s)
    for ele in b:
        c+=ele
    return c



def reverse_letter(string):
    new = [s for s in string if s.isalpha()]
    a = new
    a.reverse()
    return ''.join(list(a))



def reverse_letter(string):
    return ''.join(reversed([char for char in string if char.isalpha()]))



import string
def reverse_letter(string):
    phrase=[]
    alpha=['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
    for letter in string:
        if letter in alpha:
            phrase.append(letter)
    return ''.join(reversed(phrase))
    
reverse_letter('hello')



def reverse_letter(string):
    alphabet = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"}
    a = list(string)
    new = []
    for k in range(0,len(a)):
        if a[k] in alphabet:
            new.append(a[k])
    
    b = list(range(0,len(new)))
    
    for i in range(0,len(new)):
        b[i] = new[len(new)-1-i]
    
    out = ""
    for j in range(0,len(new)):
        out += str(b[j])
    return out



def reverse_letter(string):
    result=""
    for letter in string:
        if letter.isalpha():
           result+=letter
        else:
           del(letter)
    result2=result[::-1]
    return(result2)


def reverse_letter(string):
    return "".join(list(reversed([n for n in string if n.isalpha()])))



def reverse_letter(string):
    reversed = ''
    for char in string:
        if char.isalpha():
            reversed += char
    return reversed[::-1]



def reverse_letter(string):
    #do your magic here
    n=len(string)
    str=""
    for i in range(n):
      if string[i].isalpha() == True:
         str=str+string[i] 
        

        
        
    return str[::-1]

def reverse_letter(string):
    #do your magic here
    newString = ""
    for word in string:
        if word.isalpha():
            newString = word + newString
        
            
    return newString


def reverse_letter(string):
    r=len(string)
    s=""
    for i in range(r):
        if(string[i].isalpha()):
            s=s+string[i]
    return s[::-1]


import re
def reverse_letter(string):
    return re.sub(r"""[0-9!@#$%^&*?/ \/(/)/{/}/+/-/*/[/\]/~/`/./,/>/</'/"/?\=\\:_|\-;]""","", string)[::-1]



def reverse_letter(string):
    s = ""
    for c in string[::-1]:
        if c.isalpha():
            s += c
    return s



letters = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]
def reverse_letter(string):
    string = string[::-1]
    returner = []
    for item in string:
        if item in letters:
            returner.append(item)
    return ''.join(returner)




def reverse_letter(string):
    result = ""
    for i in range(1,len(string)+1):
        if string[-i].isalpha():
            result += string[-i]
    return result



def reverse_letter(string):
    x = filter(str.isalpha, string)
    return "".join(i for i in list(x))[::-1]

import string

def reverse_letter(s):
    abc = list(string.ascii_lowercase)
    result = []
    for i in s[::-1]:
        if i in abc:
            result.append(i)
    return "".join(result)



def reverse_letter(string):
    answer = []
    for a in string[::-1]:
        if a.isalpha() == True:
            answer.append(a)
    return ''.join(answer)

def reverse_letter(string):
    ls = list(string)
    reverse = ls.reverse()
    reversed_cleaned = ''
    for i in range(len(ls)):
        if ls[i].isalpha():
            reversed_cleaned += ls[i]
    return reversed_cleaned



def reverse_letter(string):
    reversed = ''
    length = len(string)
    for m in range(length):
        reversed = reversed + string[(length - 1) - m]
    abc = 'abcdefghijklmnopqrstuvwxyz'
    reversed_cleaned = ''
    for n in range(length):
        if reversed[n] in abc:
            reversed_cleaned += reversed[n]
    return reversed_cleaned
        


def reverse_letter(string):
    res = ''
    for i in range(len(string)-1, -1, -1):
        if string[i] in 'abcdefghijklmnopqrstuvwxyz':
            res += string[i]
    return res



import re


def reverse_letter(string):
    str = re.sub("[^a-z]", "", string)
    return str[::-1]



def reverse_letter(a):
    ans=''
    a = list(a)
    while len(a)>0:
        b = a.pop()
        if b.isalpha():
            ans = ans + b
            print(ans)
    return ans        
        


def reverse_letter(string):
    arr = list(filter(str.isalpha, string))
    arr.reverse()
    return ''.join(arr)


def reverse_letter(string):
    str = ''.join([x if x.isalpha() else '' for x in string])
    return str[::-1]



def reverse_letter(string):
    gnirts = ''
    for i in range(0,len(string)):
        if string[i].isalpha():
            gnirts = string[i]+gnirts
    return gnirts



def reverse_letter(string):
    #do your magic here
    alphabet = 'abcdefghijklmnopqrstuvwxyz'
    s = ''
    for letter in string:
        if letter in alphabet: 
            s = letter + s
    
    return s

def reverse_letter(string):
    li = []
    for i in string:
        if i.isalpha():
            li.append(i)
        else:
            pass
    return "".join(li[::-1])
    
    #do your magic here



def reverse_letter(string):
    return "".join(s for s in string if 97 <= ord(s) <= 122)[::-1]



def reverse_letter(string):
    list = ''
    list1 = list.join([c for c in string if c.isalpha()])
    return list1[::-1]




def reverse_letter(string):
    only_char = ""
    for char in string:
        if char.isalpha():
            only_char+=char
    return only_char[::-1]



def reverse_letter(line):
    letters = list(filter(str.isalpha, list(line)))
    letters.reverse()
    return ''.join(letters)



def reverse_letter(string):
    ans =[]
    for i in list(string):
        if i.isalpha():
            ans.append(i)
    a = "".join(ans)[::-1]
    return a

def reverse_letter(string):
    str = "".join(x for x in string if x.isalpha())
    return str[::-1]
                 



import pandas as pd
def reverse_letter(s):
    return ''.join([i for i in s if i.isalpha()])[::-1]



def reverse_letter(string):
    out = []
    for n in range(len(string)):
        if string[n].isalpha():
            out.insert(0, string[n])
    return ''.join(out)

def reverse_letter(string):
    word = [x for x in string[::-1] if x.isalpha()]
    return ''.join(word)



def reverse_letter(string):
    res = "".join([a for a in string[::-1] if a.isalpha()])
    return res
    


def reverse_letter(string):
    result =  list(string[::-1])
    answer = []
    for i in result:
        if i.isalpha():
            answer.append(i)
    return ''.join(answer)
        
        
    



def reverse_letter(string):
    lst = ''.join([i for i in string if i.isalpha()])
    rev = lst[::-1]
    return rev



import re

def reverse_letter(string):
    regex = re.compile('[^a-z]')
    reg = regex.sub('', string)

    reverse_word = reg[::-1]

    return reverse_word

def reverse_letter(s):
    a = [i for i in s if i.isalpha()]
    a = ''.join(a)
    return a[::-1]



import string
def reverse_letter(input_str):
    return "".join([c for c in input_str if c in string.ascii_letters][::-1])



def reverse_letter(string):
    return ''.join(i if i.isalpha() else '' for i in string)[::-1]

def reverse_letter(string):
    return ''.join((string[i] if string[i].isalpha() else "") for i in reversed(list(range(len(string)))))



def reverse_letter(string):
    return "".join(c if c.isalpha() else "" for c in string)[::-1]



def reverse_letter(string):
    #do your magic here
    alphabet="abcdefghijklmnopqrstuvwxyz"
    reversed_word = list()
    for letter in string:
        if letter in alphabet:
            reversed_word.append(letter) 
    reversed_word.reverse()
    return "".join(reversed_word)



def reverse_letter(string):
    result = ''.join(x for x in string if x.isalpha())
    return result[::-1]



def reverse_letter(string):
    lst = list(string)
    lst.reverse()
    newlst = []
    for item in lst:
        if not item.isalpha():
            pass
        else:
            newlst.append(item)
    return "".join(newlst)



def reverse_letter(string):
    outputArray = []
    for a in string:
        if a.isalpha():
            outputArray.append(a)
    outputArray.reverse()
    return "".join(outputArray)



from string import ascii_lowercase

def reverse_letter(string):
    return ''.join(l for l in string[::-1] if l in ascii_lowercase )



def reverse_letter(string):
    alphabet = 'abcdefghijklmnopqrstuvwxyz'
    x =''
    for letter in string:
        if letter in alphabet:
            x += letter
    return x[::-1]



def reverse_letter(string):
  iaprw = []
  for i in string:
    if i.isalpha() == True:
      iaprw.append(i)
  iaprw.reverse()
  return ''.join(iaprw)

def reverse_letter(string):
    lt='qwertyuiopalskjdhfgzxcvbnm'
    s=''
    for i in string:
        if i in lt:
            s=s+i
    return s[::-1]

def reverse_letter(string):
    s = ''.join(filter(str.isalpha, string))
    inverse = s[::-1]
    return inverse



def reverse_letter(string):
    reversed = ""
    for i in range(len(string)-1, -1, -1):
        if string[i].isalpha():
            reversed += string[i]
    return reversed




def reverse_letter(string):   
    result = ''.join([i for i in string if not i.isdigit()])
    alphanumeric = ''.join([i for i in result if i.isalnum()])
            
    return alphanumeric[::-1]






def reverse_letter(string):
    arr = list(string)
    arr2 = []
    for j in range(0,len(arr)):
        if arr[j].isalpha() == True:
            arr2.append(arr[j])
    return "".join(arr2[::-1])