Pivotwider

Pivot_wider is a data reshaping function in the tidyr package of the tidyverse. It converts data from a long (tall) format to a wide format by turning unique values from one column into separate columns and filling those cells with corresponding values from another column. It is commonly used to prepare data for tabular presentation or analysis that benefits from wide equations or comparisons.

Core arguments and behavior

The essential inputs are data, id_cols, names_from, and values_from. id_cols identifies the columns that define each observation and should be preserved in the output. names_from specifies which column’s unique values become the new column names in the wide format. values_from designates which column provides the values to populate the new cells. If multiple rows share the same id and name combination, you can use values_fn to specify an aggregation function (for example, mean). Missing cells can be filled with values_fill, such as 0 or NA. Additional naming and formatting options include names_prefix, names_sep, and names_glue to control how the new column names are composed. When you supply multiple values_from, multiple value columns are created.

Relation to other functions

Pivot_wider is the counterpart to pivot_longer, which converts wide to long. It also supersedes the older spread function in tidyr. Typical usage involves transforming a tidy long dataset into a wide table for easier comparison or downstream analysis.

Example (conceptual)

Pivot_wider(data, id_cols = id, names_from = category, values_from = amount) widens a dataset so that each category becomes a separate column.