head function

The head function returns in each row the first n letters of the corresponding value in the column.


Parameters

head(column, nchar)

If you are using continuous attributes, check the Flow Execution Parameters.

Parameter

Description

column

The nominal attribute containing the strings. If the column is not nominal, it will be casted to nominal upon function’s computation. The column parameter is mandatory.

nchar

The number of letters we want to select for each string in the column. It can be either a specified value or an integer attribute. The nchar parameter is mandatory.


Example

The following example uses the Adult dataset.

Description

Screenshot

In this example, we want to transform the Sex attribute values into their initial. Add a new attribute, called newvalues, and write the following formula:

head($"sex",1)

The function has returned the first letter of each value in the corresponding row.