Power Query lets you perform a series of steps to transform your Excel data. There are times when we want to do things that are not built in the user interface. This is possible with Power Query’s programming language, which is M.
Unfortunately not all of Excel’s formulas can be used in M.
For example, if we want to use the LEN Excel Function to get the length of strings, it is not supported in M.
Let me show you how I can replicate the LEN Function in M!
Let’s go through the steps in detail:
STEP 1: Select your data and turn it into an Excel Table by pressing the shortcut Ctrl + T or by going to Insert > Table
STEP 2: Go to Data > Get & Transform > From Table (Excel 2016) or Power Query > Excel Data > From Table (Excel 2013 & 2010)
Excel 2016:
 
Excel 2013 & 2010:
STEP 3: This will open up the Power Query Editor.
We want to get the length of the Channel Partners, so we need to select the CHANNEL PARTNERS column.
Go to Add Column > Add Custom Column
STEP 4: Let us create a simple M expression to replicate the LEN function in Excel.
In the New column name text box, type CHANNEL PARTNERSÂ (LEN)
In the Custom column formula, type in: Text.Length(
From the Available columns choose CHANNEL PARTNERSÂ and select Insert.
Then finish off the formula by entering  )Â
We now have build the following formula:
Text.Length([CHANNEL PARTNERS])
So lets quickly break down what we just did:
- We are using the Text.Length formula to get the length of the CHANNEL PARTNERS column
- Click OK to confirm.
Now you will see your changes take place.
STEP 5: Click Close & Load from the Home tab and this will open up a brand new worksheet in your Excel workbook with the updated values.
Congratulations! You have used a M formula for replicating the LENÂ function!
