How to use Power Query to load and clean data

Power Query is a powerful data transformation and data loading tool available in Microsoft Excel and Power BI. It allows you to connect to various data sources, load data into a workbook or data model, and perform data cleaning and transformation operations. Here's a step-by-step guide on how to use Power Query to load and clean data: 

1.     Open Excel or Power BI and go to the "Data" tab.
2.     Click on the "Get Data" button and select the desired data source from the available options (e.g., Excel workbook, CSV file, database, web, etc.).
3.     In the Power Query Editor window that opens, you'll see a preview of the data. If needed, you can apply various transformations to clean and shape the data.

a.      Remove unwanted columns: Select the columns you want to remove and click on the "Remove Columns" button in the "Home" tab.
b.     Rename columns: Right-click on a column header and choose the "Rename" option to give it a more descriptive name.
c.      Change data types: Select the columns and choose the appropriate data type from the "Data Type" dropdown in the "Transform" tab.
d.     Filter data: Use the filtering options in the "Home" tab to exclude rows based on specific conditions.
e.      Split columns: If a column contains multiple values separated by a delimiter, you can split it into multiple columns using the "Split Column" feature in the "Transform" tab.
f.       Merge columns: Combine two or more columns into a single column using the "Merge Columns" option in the "Transform" tab.
g.      Remove duplicates: Remove duplicate rows by selecting the columns to consider for duplication and clicking on the "Remove Duplicates" button in the "Home" tab.
h.     Fill missing values: To fill in missing values, select the desired column(s), go to the "Transform" tab, and choose an appropriate option like "Fill Down" or "Replace Values."
i.       Perform calculations: Use the available functions and operators in Power Query to create new calculated columns.

 
4.     As you apply transformations, the preview data in Power Query Editor will update in real-time, allowing you to see the results immediately.
5.     Once you have finished cleaning and transforming the data, click on the "Close & Load" button to load the cleaned data into Excel or Power BI.
6.     Choose the desired destination for the loaded data, such as a new worksheet or a data model.
7.     The cleaned data will be loaded, and any further changes made to the original data will require re-loading or refreshing the query. 

Power Query provides a wide range of data cleaning and transformation capabilities, and the above steps cover some common tasks. However, the specific steps and options may vary depending on your version of Excel or Power BI. Experimenting with the available features and exploring the Power Query documentation can help you discover additional functionality to meet your data cleaning needs.