Functions should return a data frame if possible, not a matrix

[sfcheung]

Status

On-Hold: This change may break some functions. It is not of high priority because basic matrix subsetting is not difficult to learn.

Note

When users see a table, they expect that it is a data frame. Some users may not know how to work with a matrix.

To-Do

• [ ] Check all functions that return a matrix and see if it is OK to return a data frame. No need to add an argument to select the type. Users who like matrix will know how to convert the output to a matrix.
• [ ] Check all functions that may use the output from another function. Include a check for class. If it is a data frame and the function cannot handle a data frame, try to convert it to a matrix internally.

[sfcheung]

No longer necessary as user-friendly print-methods have been added the output of all major functions. Closing this issue.