Value Mapping is taking the value of one column and using it to replace the value of that same column or create a new value for another column. It works by looking at the original value, determining if it matches the rules that you’ve set and then using those rules to determine the new value that will take its place.
How to Use Numetric for Value Mapping
- Go to the Datasets tab
- Create a new field or select a field where the new values will be placed
- Click the “Add Transformations” button and select “Value Map”
- Select the variable you would like to map from the drop down in the “Map From” section
- Enter the original values on the left and what the new value will be on the right
- Click the plus icon to add the mapping to the list
- Repeat steps 5-6 as many times as necessary to create the desired values
- To remove a value hover over the blue equal sign and it will turn into a red x
- Reindex the data by clicking the Reindex button in the top right
One use of value mapping is to combine like variable entries. In the example below we have a variable labeled “Time” which contains the time of day each transaction took place. We will use this variable to create a new variable which groups those times into the different parts of the day.
Another common use of value mapping is cleaning data entry errors. Sometimes data is entered incorrectly and this is a handy way to fix data errors within Numetric.
MAP VALUES ARE REGULAR EXPRESSIONS – This option scans the variable for a partial match and returns the new value if it is found. Perl based regular expressions can also be used.