To send a message to a data column, you have to be able to refer to the column. There are several ways to refer to columns, some of which also return column object references. You can simply refer to a column by name, using the colon prefix to make sure JMP scopes the name as a data column. You can also combine the column reference with a data table reference using a colon too. For example, this line scopes the name ratio to a data column, while this line combines the column reference with a reference to the data table object reference stored in the variable dt. The form that explicitly identifies the data table is recommended, just in case there might be several data tables open when your script is running. Both forms can be used to cast a column into an analysis role in a platform launch, and to send a message to a column. However, these forms do not return a column object reference. So, you can also use the Column function to refer to a data table column, which does return a valid column reference. This function uses either a character string for the name, or an index into the data table. And you can optionally include a data table reference as the first argument to ensure that the reference is correct -- which again, is a recommended practice. So the examples of the Column function shown here can be used to obtain an object reference for a column, which could be stored in a variable. And, this syntax also allows you to cast a column into an analysis role in a platform launch, and to receive messages.
