#MATL, 18 14 13 bytes

4e!Z{Zc12XOXk

Input is provided as a string (enclosed in single quotes).

This version only runs in MATL on MATLAB since MATLAB is able to automatically parse datestr('2016 04').

Explanation

        % Implicitly grab input as a string
4e!     % Reshape input to be 2 x 4 (puts the year in row 1 and month in row 2)
Z{      % Place each row in a separate cell
Zc      % Join them together using a space to create 'yyyy mm' format
12      % Number literal, pre-defined datestring of 'mmmyy'
XO      % Convert from serial date number to string using this format
Xk      % Convert to uppercase
        % Implicitly display
    

Here is an 18 byte version which works on Octave (and therefore the online interpreter)

'yyyymm'2$YO12XOXk

Try it Online

Modified version for all test cases

Explanation

            % Implicitly grab input as a string
'yyyymm'    % Push the format string as a string literal
2$YO        % Convert to a serial date number
12          % Number literal, pre-defined datestring of 'mmmyy'
XO          % Convert from serial date number to string using this format
Xk          % Convert to uppercase
            % Implicitly display

MATL, 18 14 13 bytes

4e!Z{Zc12XOXk

Input is provided as a string (enclosed in single quotes).

This version only runs in MATL on MATLAB since MATLAB is able to automatically parse datestr('2016 04').

Explanation

        % Implicitly grab input as a string
4e!     % Reshape input to be 2 x 4 (puts the year in row 1 and month in row 2)
Z{      % Place each row in a separate cell
Zc      % Join them together using a space to create 'yyyy mm' format
12      % Number literal, pre-defined datestring of 'mmmyy'
XO      % Convert from serial date number to string using this format
Xk      % Convert to uppercase
        % Implicitly display
    

Here is an 18 byte version which works on Octave (and therefore the online interpreter)

'yyyymm'2$YO12XOXk

Try it Online

Modified version for all test cases

Explanation

            % Implicitly grab input as a string
'yyyymm'    % Push the format string as a string literal
2$YO        % Convert to a serial date number
12          % Number literal, pre-defined datestring of 'mmmyy'
XO          % Convert from serial date number to string using this format
Xk          % Convert to uppercase
            % Implicitly display

#MATL, 18 14 bytes

4:&)Owv!12XOXk

Input is provided as a string (enclosed in single quotes).

This version only runs in MATL on MATLAB since MATLAB is able to automatically parse datestr('2016 04').

Explanation

        % Implicitly grab input as a string
4:&)    % Break into the first 4 characters (the year) and the last two (the month)
Owv!    % Insert a null character between the year and month
12      % Number literal, pre-defined datestring of 'mmmyy'
XO      % Convert from serial date number to string using this format
Xk      % Convert to uppercase
        % Implicitly display
    

Here is an 18 byte version which works on Octave (and therefore the online interpreter)

'yyyymm'2$YO12XOXk

Try it Online

Modified version for all test cases

Explanation

            % Implicitly grab input as a string
'yyyymm'    % Push the format string as a string literal
2$YO        % Convert to a serial date number
12          % Number literal, pre-defined datestring of 'mmmyy'
XO          % Convert from serial date number to string using this format
Xk          % Convert to uppercase
            % Implicitly display

#MATL, 18 14 13 bytes

4e!Z{Zc12XOXk

Input is provided as a string (enclosed in single quotes).

This version only runs in MATL on MATLAB since MATLAB is able to automatically parse datestr('2016 04').

Explanation

        % Implicitly grab input as a string
4e!     % Reshape input to be 2 x 4 (puts the year in row 1 and month in row 2)
Z{      % Place each row in a separate cell
Zc      % Join them together using a space to create 'yyyy mm' format
12      % Number literal, pre-defined datestring of 'mmmyy'
XO      % Convert from serial date number to string using this format
Xk      % Convert to uppercase
        % Implicitly display
    

Here is an 18 byte version which works on Octave (and therefore the online interpreter)

'yyyymm'2$YO12XOXk

Try it Online

Modified version for all test cases

Explanation

            % Implicitly grab input as a string
'yyyymm'    % Push the format string as a string literal
2$YO        % Convert to a serial date number
12          % Number literal, pre-defined datestring of 'mmmyy'
XO          % Convert from serial date number to string using this format
Xk          % Convert to uppercase
            % Implicitly display

#MATL, 18 14 bytes

4:&)XhZc12XOXk

Input is provided as a string (enclosed in single quotes).

This version only runs in MATL on MATLAB since MATLAB is able to automatically parse datestr('2016 04').

Explanation

        % Implicitly grab input as a string
4:&)    % Break into the first 4 characters (the year) and the last two (the month)
Xh      % Combine these two parts into a cell array
Zc      % Join them together with a space in between
12      % Number literal, pre-defined datestring of 'mmmyy'
XO      % Convert from serial date number to string using this format
Xk      % Convert to uppercase
        % Implicitly display
    

Here is an 18 byte version which works on Octave (and therefore the online interpreter)

'yyyymm'2$YO12XOXk

Try it Online

Modified version for all test cases

Explanation

            % Implicitly grab input as a string
'yyyymm'    % Push the format string as a string literal
2$YO        % Convert to a serial date number
12          % Number literal, pre-defined datestring of 'mmmyy'
XO          % Convert from serial date number to string using this format
Xk          % Convert to uppercase
            % Implicitly display

#MATL, 18 14 bytes

4:&)Owv!12XOXk

Input is provided as a string (enclosed in single quotes).

This version only runs in MATL on MATLAB since MATLAB is able to automatically parse datestr('2016 04').

Explanation

        % Implicitly grab input as a string
4:&)    % Break into the first 4 characters (the year) and the last two (the month)
Owv!    % Insert a null character between the year and month
12      % Number literal, pre-defined datestring of 'mmmyy'
XO      % Convert from serial date number to string using this format
Xk      % Convert to uppercase
        % Implicitly display
    

Here is an 18 byte version which works on Octave (and therefore the online interpreter)

'yyyymm'2$YO12XOXk

Try it Online

Modified version for all test cases

Explanation

            % Implicitly grab input as a string
'yyyymm'    % Push the format string as a string literal
2$YO        % Convert to a serial date number
12          % Number literal, pre-defined datestring of 'mmmyy'
XO          % Convert from serial date number to string using this format
Xk          % Convert to uppercase
            % Implicitly display