---
title: "Column Parsers"
slug: "column-parsers"
updated: 2022-07-27T21:11:44Z
published: 2022-07-27T21:11:44Z
canonical: "code.tag.bio/column-parsers"
---

> ## 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.

# Column Parsers

The *column* **parser** is the abstract parent type for a wide variety of other **parsers** which load data from one or more columns in the source data.

As an abstract type, it is not possible to instantiate a *column* type **parser** - only its child types.

**Parser** types which inherit from the *column* type are designed to create and load data into **categorical** or **numeric** `variables` within `collections`. They will typically include some of the following common attributes.

## column

The `column` attribute links the column name in the source data table to the Tag.bio system.

```
{
  "parser_type": "ptpt", 
  "column": "cccc"
}
```

## nesting column parsers

Source data sometimes requires a sequence of manipulations before it is usable. The `column` attribute of a **parser** can itself contain another **parser**. When nested this way, each **parser** is completed starting first with the *inner most* and finishes with the parent **parser**.

```
{
  "parser_type": "tttt", 
  "column": {
    "parser_type": "tttt",
    "column": "cccc"
  }
}
```