Create

Create new variables from existing variables by doing arithmetic on them.

Type the desired variable name in the left-hand box and any valid R expression in the right-hand box. The expression can use existing variable names, arithmetic operators, and R functions.

Examples:

• income = hours * payrate
• weight.diff = end.weight - begin.weight
• average.weight = (begin.weight + end.weight) / 2
• bmi = weight / height^2

The new variable name is automatically converted to a valid name if needed (e.g., spaces replaced with dots).

Build expressions using the interactive calculator interface:

1. Select a column from the dropdown to add a variable to the expression
2. Select an operation (+, -, *, /, ^, (, ), :) to combine variables
3. Use the number pad to enter numeric constants
4. Give the new variable a name in the text field
5. Click Create Variable to add the result to the dataset

The expression is shown in the preview area as you build it. Use the del button to remove the last item from the expression.

Add Columns

You can also add a column by pasting raw values directly. Go to Manipulate Variables > Add Columns.

1. Type or paste values into the text area — either comma-separated on a single line, or one value per line (preferred, especially if values contain commas)
2. Check Numeric input if the values are numbers (otherwise they are added as categorical)
3. Click Add as column to append the new column to the dataset

If the list of values is shorter than the number of rows, it is recycled (repeated) to fill the column. If it is longer, it is truncated.