--- title: "categorical-compound" slug: "categorical-compound-parser" updated: 2022-12-13T00:10:55Z published: 2022-12-13T00:10:55Z canonical: "code.tag.bio/categorical-compound-parser" --- > ## Documentation Index > Fetch the complete documentation index at: https://code.tag.bio/llms.txt > Use this file to discover all available pages before exploring further. # categorical-compound The `categorical-compound` **parser** will load data from two or more columns in a source data table and concatenate their values to become multiple categorical **variables** within a **collection**. ``` { "parser_type": "categorical-compound", "table_alias": "tata", "columns": [ "ccc1", "ccc2" ], "operator": ", ", "collection": "collection_name" } ``` ## columns **usage: *required*** The `columns` attribute specifies two column names to produce values for concatenation. ## operator **usage: *optional*** The `operator` attribute specifies the delimiter string to be included between concatenated values and will default to a value of " " (a single-space string).