How-to | Fill empty cells of a column with the value of the corresponding row from another column#

Handling missing data is one data preparation challenge that analysts routinely face. Let’s review one way to fill in missing data.

This example demonstrates filling the empty cells of a column with values of the corresponding rows from another column.

Coalesce function#

In a Prepare recipe, use the Formula processor with the coalesce() function as shown below:

../../_images/kb-coalesce-1.png

Here we fill the empty values of `col1` with the corresponding values of `col2` in a new column.#

You can also specify multiple columns, or even directly specify the missing values.

../../_images/dimitri_0-1588874053641.png

Here we fill the empty values of `col1` with the values of `col2`, or `0` when `col2` is also empty.#

The Formula language gives you the flexibility to achieve more customized tasks. For example, you can combine functions in the same expression.

../../_images/kb-coalesce-3.png

Here we fill the empty values of `col1` with the corresponding floored values of `col2` in a new column.#

See also

See Concept | Dataiku formulas to learn more.