Converting a string to lower-case (without built-in to-lower functions!)

Question

The goal of this code-golf is to create a code that lets the user input an ASCII string (contains only printable ASCII characters), and your program outputs the lower-case variant of this string.

Important: you are NOT allowed to use a built-in function that converts the string (or just one character) to lowercase (such as ToLower() in .NET, strtolower() in PHP , ...)! You're allowed to use all other built-in functions, however.

Another important note: The input string doesn't contain only uppercase characters. The input string is a mix of uppercase characters, lowercase characters, numbers and other ASCII printable characters.

Good luck!

Answer 1

Thunno 2, 2 bytes

RP

Attempt This Online! Port of user8777's Python answer.

Thunno 2, 4 bytes

kAẠṆ

Attempt This Online! No uppercase/swap-case built-ins here.

Thunno 2, 12 bytes

ıDkAsƇ?C32+C

Attempt This Online! No uppercase/swap-case/transliterate built-ins here.

Explanation

RP  # Implicit input
R   # Convert to uppercase
 P  # Swap the case of each character
    # Implicit output

kAẠṆ  # Implicit input
   Ṇ  # Transliterate the input
kA    # (from) the uppercase alphabet
  Ạ   # (to) the lowercase alphabet
      # Implicit output

ıDkAsƇ?C32+C  # Implicit input
ı             # Map over the input string:
 D            #  Duplicate it
    sƇ        #  Pop one copy, and check if it's in
  kA          #  the uppercase alphabet
      ?       #  If it is:
       C      #   Convert to codepoint
        32+   #   Add 32
           C  #   And convert to character
              #  Otherwise, the character stays on top
              # Implicit output, joined

Answer 2

Japt, 7 5 bytes

;dBíC

Try it here

Answer 3

Itr, 17 bytes

#µ»ä26¹64+=S32*+«

Reads string (surrounded by quotes) from standard input, prints the result to standard output

online interpreter

Explanation

#             ; read the string from standard input
 µ»   «       ; apply to each element
              ; implicitly print the result

ä             ; duplicate the character
 26¹64+       ; push the range from 65 to 90 ('A' through 'Z')
       =      ; vectorized equality check (of character and range)
        S     ; sum up the vector (1 if the char is in range, 0 otherwise)
         32*+ ; multiply by 32 and add to the character
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