# Tableau Prep Builder: Cleaning / Cleansing data (Part 3 of 7)

> This is content from just-tim, the data-and-analytics channel by Tim Ngwena (formerly 'Tableau Tim'). Tim has 12+ years of hands-on BI experience and covers Tableau most of all, plus Power BI, Looker, Hex, SQL and data modelling, the analytics industry, and the craft of doing the job — always tool-agnostic and honest about the trade-offs.

- **Author:** Tim Ngwena (just-tim, https://just-tim.com/about)
- **Published:** 2020-01-27
- **Format:** Video · 18 min watch · transcript available
- **Topics:** Data prep, Data visualisation
- **Tools:** Excel; Tableau (calculated fields, data roles, prep)
- **Canonical:** https://just-tim.com/posts/tableau-prep-builder-cleaning-cleansing-data-part-3-of-7
- **Watch:** https://www.youtu.be/YA5nvQXGXK4

This is the third video in my Tableau Prep for Excel users series, focusing on the clean step. Using the sample flow that ships with Tableau Prep, I walk through the summary view, data types and data roles, making and reordering changes, filtering rows, and grouping similar values, contrasting each with how you'd do it manually in Excel.

## Key takeaways

- The clean step's toolbar adapts to the column you select and its data type, offering split, filter and calculation options for text but a reduced set for integers and dates.
- Data roles such as city, postal code and country let you tag columns with geographic metadata that downstream tools pick up automatically for mapping and analysis.
- Changes within a clean step aren't strictly sequential, so you can delete, reorder or drag steps, though reordering can break later steps that depend on earlier ones.
- Group and Replace can cluster misspelled values automatically using pronunciation, common characters or spelling, and you can also build groups manually.
- The bottom preview is a live Tableau view of your data, letting you drill from the high-level aggregate summary down to individual problem rows.

## Chapters

- 0:44 Cleansing data in Excel
- 4:09 The clean step and summary window
- 6:51 Data types and data roles
- 7:52 Recommendations and managing changes
- 11:00 Filtering and excluding rows
- 11:41 Group and replace similar values
- 14:14 Tracing columns and calculations
- 16:56 Reordering and renaming columns

Watch the full video, read the transcript and use chapter deep-links on the page: https://just-tim.com/posts/tableau-prep-builder-cleaning-cleansing-data-part-3-of-7

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just-tim — Data and analytics, with a point of view. · https://www.youtube.com/channel/UC7HYxRWmaNlJux-X7rNLZyw · https://twitter.com/TableauTim · https://www.linkedin.com/in/timngwena