I meet this requirement from time to time.
Each time I start from scratch. This time I decided to put a note here.
A pretty simple task is to convert a number, say 3 to a column, like C. Or, not less obvious, 1467 to BDK.
Here's the code for int to column name conversion (without additional checks) and back:
* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZB74H_NEXUS_GSHEETS_READWRITE=>GET_COLUMN_FROM_INT
* +-------------------------------------------------------------------------------------------------+
* | [--->] IV_COLUMN_NUM TYPE INT4
* | [<-()] RV_RESULT TYPE STRING
* +--------------------------------------------------------------------------------------</SIGNATURE>
METHOD get_column_from_int.
CHECK iv_column_num > 0.
DO.
DATA(lv_mod) = ( iv_column_num - 1 ) MOD 26.
DATA(lv_div) = iv_column_num DIV 26.
iv_column_num = lv_div.
rv_result = sy-abcde+lv_mod(1) && rv_result.
IF iv_column_num <= 0.
EXIT.
ENDIF.
ENDDO.
ENDMETHOD.
* <SIGNATURE>---------------------------------------------------------------------------------------+
* | Static Public Method ZB74H_NEXUS_GSHEETS_READWRITE=>GET_INT_FROM_COLUMN
* +-------------------------------------------------------------------------------------------------+
* | [--->] IV_COLUMN TYPE STRING
* | [<-()] RV_RESULT TYPE INT4
* +--------------------------------------------------------------------------------------</SIGNATURE>
METHOD get_int_from_column.
DO.
IF iv_column IS INITIAL.
RETURN.
ENDIF.
FIND iv_column(1) IN sy-abcde MATCH OFFSET DATA(lv_offset).
rv_result = rv_result * 26 + lv_offset + 1.
iv_column = iv_column+1.
ENDDO.
ENDMETHOD.
