Remove excess spaces in Power Query

I showed various methods to remove additional spaces in Excel in a previous post. One of the methods involved creating a custom function in Power Query. As this is a more advanced method, I wanted to go a bit deeper and describe the method to remove excess spaces in Power Query.

Excel TRIM vs. Power Query Trim

Excel’s TRIM function removes leading spaces, trailing spaces, and multiple spaces from the middle (known as an inner trim) of a text string. It’s an excellent function for cleaning dirty data.

Power Query’s Trim function, by comparison, only removes leading and trailing spaces; the spaces in the middle of the string remain.

It’s very rare we would ever want multiple spaces within a text string, yet they are not uncommon when dealing with dirty data. So, how can we get Power Query to replicate Excel’s capabilities?

Find and replace to remove double spaces

One option to solve this problem is to repeatedly use the replace values step on a text string until all the excess spaces have been removed.

To do this:

• Select the column containing double spaces
• Click Transform > Replace Values
• In the Replace Values box, enter double spaces in the Value to Find box, and a single space in the Replace with box
  
• Finally, click OK

If you have more than 3 spaces together, this will not remove all instances of excess spaces. Therefore, we need to repeat this action until all excess spaces have been removed.

While this method works, what if we refresh and there are 5 spaces or 8 spaces together? We just don’t know many times to undertake the transformation to ensure it provides the correct result. Instead, we need to find a better option.

Custom function

We want to remove double spaces in Power Query with a single transformation, no matter how many spaces there are. For this, we will use a custom function.

There are two approaches to creating custom functions in Power Query:

1. Create the transformations using the user interface, then convert it to a function
2. Create the function from scratch by writing the M code ourselves

I usually advise the first where possible, as it is easier to get started. However, for this transformation, it is easier to write the code with a little bit of formula knowledge.

For a more detailed guide on creating custom functions, check out this post: Power Query – Custom Functions

Power Query functions

The functions we are using are:

Text.Split

Returns a list of text values after splitting the value based on a specific delimiter/separator,

Text.Split(text as text, separator as text) as list

More info: https://docs.microsoft.com/en-us/powerquery-m/text-split

List.Select

Returns a list of values from a list that match the selection criteria.

List.Select(list as list, selection as function) as list

More info: https://docs.microsoft.com/en-us/powerquery-m/list-select

Text.Combine

Returns the result of combining a list of text values into a single string, which can be joined with a separator between each element.

Text.Combine(texts as list, optional separator as nullable text) as text

More info: https://docs.microsoft.com/en-us/powerquery-m/text-combine

Understanding the custom function

Using the 3 formulas listed above, we will undertake a 3 step process:

1. Split the text value into a list with the split occurring at each occurrence of the space character. This converts all spaces into empty strings
2. Remove the empty strings from the list
3. Re-join the list together and insert a single space between each word.

We only require a single argument; the text string on which to perform the function.

(textValue as text)=>

let
    //Split the text at each space character
    SplitText = Text.Split(textValue," "),
    //Remove the blank items from the list
    ListNonBlankValues = List.Select(SplitText,each _<> ""),
    //Join the list with a space character between each item
    TextJoinList = Text.Combine(ListNonBlankValues," ")
in
    TextJoinList

Create the custom function

To create a custom function, perform the following steps:

1. In Power Query, click Home > New Source (dropdown) > Other Sources > Blank Query
   
   
2. Rename the query to fxTrim. You can call it anything you like, but “fx” is commonly a used prefix to identify custom functions.
3. Click View > Advanced Editor
4. Enter the code above into the Advanced Editor window
5. When finished, click Done
   
   

The function is now ready to use.

Using the custom function

Now let’s use the custom function on our Table.

1. Click Add Column > Invoke Custom Function
2. In the Invoke Custom Function window:
   • Provide the name of the new column to be created
   • Select fxTrim from the list of functions
   • Enter the column on which to perform the transformation.
3. Finally, click OK.

Ta-Dah!

The new column now contains cleaned text values with no excess spaces. Woop Woop!!!

Still have spaces?

If you still have spaces, it’s likely they are either non-printing characters or a non-breaking spaces. Apply the following transformations before the space removal steps detailed above.

Remove non-printing characters with clean

Non-printing characters are items such as null, line-feed and carriage returns. They have character codes of 0 to 31. To remove non-printing characters:

• Select the column
• Click Transform > Clean from the ribbon

Covert non-breaking space character to space

The non-breaking space (known as nbsp) character is often found on web pages as a way to force white space onto the page. This has a character code of 160 and is not removed by clean or trim transformations.

Visually, this character is a space, so let’s convert it into a space:

• Select the column
• Click Transform > Replace Values from the ribbon
• In the Replace Values window, click into the value to find box then click Advanced option > Relace using special character > Insert special character > Non-breaking space. This will enter #(00A0) into the box. #(00A0) is Power Query code for a nbsp character.
• Enter a space into the replace with box
• Click OK

Conclusion

It is a shame Power Query’s Trim function does not match Excel’s functionality. But thankfully, this doesn’t stop us. We can create our own function to remove unwanted spaces in Power Query.

And maybe, not having the same functionality actually makes things more flexible for us 😀

What to know more about:

• Removing spaces in Excel? Check out this post: 7 ways to remove additional spaces in Excel
• Custom functions in Power Query? Check this out: Power Query: Custom Functions