Inverse perspective is an operation that converts multiple columns into attribute-value pairs, suitable for structured data processing in data analysis. First select the column that needs inverse perspective, right-click to select "Inverse perspective column" to generate two columns: "Properties" and "Value". Frequently asked questions include: 1. Do not select wrong columns to avoid unnecessary columns participating in operations; 2. The column names should be unified and meaningful to prevent errors in subsequent analysis; 3. After inverse perspective, you need to check and convert the data type of the "Value" column. Applicable scenarios such as converting monthly columns into date and sales formats to draw line charts, cleaning wide table data, etc. Mastering its logic can significantly improve data processing efficiency.

Sometimes the data we get is a sorted summary table, but if you want to restore it to a detailed table format, you need to use the "Inverse Perspective" function of Power Query in Excel. In fact, this operation is not that mysterious. As long as you master the steps, it will be processed quickly.

What is "inverse perspective"?

Simply put, "inverse perspective" is to convert multiple columns into attribute-value pairs. For example, you have a table that counts sales by month. Each month is a column name, and after inverse perspective, it will become two columns: one is "month" and the other is "sales".

This is very common in data analysis, especially when you need to use this data to chart or model, this structure is easier to handle.

How to use Power Query for inverse perspective?

First, make sure your data has been imported into the Power Query Editor:

1. Select the data area
2. Click "From Table/Area" in the "Data" tab (provided that your data is already in the table format)
3. After opening Power Query, you can start the operation

The steps are as follows:

• Select multiple columns you want to reverse perspective (Ctrl can be pressed and held to select multiple times)
• Right-click any selected column name
• Select the "Inverse Perspective Column" option

After you finish, you will see that the original multiple columns have become two columns: "Properties" and "Value". If your original column name represents time or category, then the "Properties" column corresponds to these names, and the "Value" column is the corresponding data.

Frequently Asked Questions and Notes

1. Don't select the wrong column

Be sure to confirm that only the columns you want to expand are selected before inverse perspective. For example, columns like "product name" that do not need to be moved should be retained. Otherwise, the results may be confusing.

2. If the column name is not a number or a classification label

If some column names are units, descriptions, or other irregular content, inverse perspective itself will not report an error, but problems may occur during subsequent analysis. It is recommended to check in advance whether the listing is unified and meaningful.

3. Data type issues

The "Value" column after inverse perspective may be of text type by default. If it is numerical data, remember to convert it manually. You can click "Convert" → "Data Type" → select the appropriate type in Power Query.

Examples of applicable scenarios

Common usage scenarios include but are not limited to:

• Convert quarterly reports into long format for visual presentation
• Convert year columns to time dimensions for trend analysis
• Cleans wide table data exported from the system to make it suitable for database import

For example, you have a sales data table with the column names "Product Name", "2023-01", "2023-02"... You can inversely view these monthly columns into two columns "Date" and "Sales" so that you can draw a line chart directly.

Basically that's it. Inverse perspective is a small feature, but it can save a lot of trouble if you use it well, especially when you have to deal with a large amount of structured data. The key is to understand the logic behind it, not to memorize the operation steps.

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