js single line code solution:

const caesarCipher = (s, k) => (String.fromCodePoint(...[...s].map((char,idx,arr,currCodePoint)=>(currCodePoint = char.codePointAt(0),(currCodePoint<=90&&currCodePoint>=65)?(((currCodePoint + k)-65)%26+65):((currCodePoint<=122&&currCodePoint>=97)?(((currCodePoint + k)-97)%26+97):(currCodePoint))))));

def caesarCipher(s, k):
low='abcdefghijklmnopqrstuvwxyz'
up= low.upper()
new=''

for i in s:
    if i in low:
        real_r= (low.index(i)+k)%26
        new+= low[real_r]
    elif i in up:
        real_r= (up.index(i)+k)%26
        new+= up[real_r]
    else:
        new+= i
return new

def caesarCipher(s, k):
        alphabet = "abcdefghijklmnopqrstuvwxyz"
        res = ""
        for c in s:
                is_upper = c.isupper()
                idx = alphabet.find(c.lower())
                if idx != -1:
                        new_idx = (idx + k) % 26
                        res += alphabet[new_idx].upper() if is_upper else alphabet[new_idx]
                else:
                        res += c

        return res

did it using ascii value in Java public static String caesarCipher(String s, int k) { String s1 = ""; int k1;

for (int i = 0; i < s.length(); i++) {
    char c = s.charAt(i);
    if (c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z') {
        k1 = k;

        while (k1 > 0) {
            if (Character.isLowerCase(c) && c + k1 <= 'z') {
                c = (char) (c + k1);
                break;
            } else if (Character.isLowerCase(c) && c + k1 > 'z') {
                k1 -= ('z' - c + 1);  
                c = 'a';  
            } else if (Character.isUpperCase(c) && c + k1 <= 'Z') {
                c = (char) (c + k1);
                break;
            } else if (Character.isUpperCase(c) && c + k1 > 'Z') {
                k1 -= ('Z' - c + 1); 
                c = 'A'; 
            }
        }

        s1 += c;
    } else {
        s1 += c; 
    }
}

return s1;

}

def shiftLetter(ch, shift): sub_const = ord('z') - ord('a') + 1 shift = shift % 26 numval = ord(ch)+shift
upper = ch.isupper()

if upper:  # case it's uppercase
    if numval > ord('Z'):  # check if have to reset to 1
        numval = numval - sub_const
else:  # case it's lowercase
    if numval > ord('z'):
        numval = numval -  sub_const
return chr(numval)

def caesarCipher(s, k): # Write your code here new_s = str() for c in s: if c.isalpha(): ch = shiftLetter(c, k) else: #non alpha chars ch = c new_s += ch return new_s