Power Automate Expression Union – Return Unique Values

Power Automate Expressions – union
Using union to remove duplicates on two different collection arrays

This blog will be looking at an expression called union() This expression can be used to remove duplicates from 2 collections. In this example, I will be using an Excel file to demonstrate this. But this can be done with any data

The Scenario

I will be taking an Excel file that has many Paper Items.

We want to remove all the duplicate items from the Plastic Item column. Why would we want to do this?
One reason may be that we get this file from a 3rd party, but we only care about the unique items to import into another system (CRM, CDS/Dynamics, SharePoint, Etc.)

Steps

First we want to add an Initialize variable, Type = Array
Next, we need to get the data we want to use. In this example I am using List rows present in a table

Now we add a Apply to each loop, and use the dynamic content value from our Excel action
Inside the Loop we add a Append to array variable action, and add the column we want to remove duplicates from. In this example Paperitem

We are done inside the loop..

Outside the loop we add a Compose action, this is where we will put the expression union
In the Expression tab type union()
Select the dynamic content tab and pass the array variable to union twice
(Click your variable comma click variable again) Your expression should look something like this:

union(variables('paperItemArray'),variables('paperItemArray'))

Done!!

Final Thoughts

Now we have a Array of all unique Plastic Items, which can be imported into another system based on your needs.

Thanks for reading!


Power Automate Tips and Tricks for Beginners

In this post, I wanted to share some of the tips and tricks that I have learnt and came across. Some of these tips I will cover the basic fundamentals so you can start using them to help you build you Flows with less pain and more fun!

1. Compose

Compose actions, are one of my favorite actions to use. They are so robust and can display pretty much anything. Compose can be found under
Data Operation > Compose

1.1

Add a Compose action before a Condition to check what values are being evaluated. In this example, my condition is saying:
If length of value is greater than 0
I add a Compose action before the condition, with the same value I am using in the condition. This allows me to check the run and see the value being evaluated
Example:

1.2

If Flow is spitting out errors about a wrong data type or you keep getting unexpected values – Since Compose can hold just about any data type. We can add one and check what the value is in run history.

1.3

Compose actions are great for doing expressions – We can add a Compose action and do expressions in the input, instead of writing the expression directly inside another action. This is handy if you need to do multiple expressions, or error checking.

2. Meaningful Names

There is nothing worse than leaving the default names for all your actions. This can be confusing, which can cause errors which could have been avoidable.
This tip is going off tip #1.

2.1

The picture below shows a bunch of Compose actions
Left: Default names used – Makes it very hard to know which action is what
Right: Custom names used – Changing the names to something meaningful allows actions to be easily found and referenced.

2.2

For awhile now, Power Automate has had a limitation with renaming actions that were being referenced in other places. That has since changed. We can now rename action that are being referenced in other actions!
For example:
The left picture shows the Compose action named ‘Compose Project’ and is being referenced by the condition below.
Changing the Compose action name to ‘Project Name’ also changes the name in the referenced condition, which is shown in the right picture.

—–NOTE —–
Limitations still exist.. The reference will not be updated if the action is in a expression OR inside a Loop. And will throw an error of:
Template Validation Failed
.
So it is always best to rename actions right away
—————

2.3

When using Expressions, to better understand and show others what is going on. Comments are great for this. For example, if using a complex expression I like to copy the expression and put into a comment of that action:

3. Scopes

Scopes are handy, they can be used for grouping actions together. In this guide I will show how to use scopes to group actions together. There are many advanced techniques that scopes can be used for, but for this demo I will be showing the very basics. Scopes can be found under
Condition > Scope

I will add 2 scopes, one for Users, and one for Accounts
To add actions in the scope, Click and Drag the action into the scope

Drag the actions in so the order of the actions remain the same. For example, I put the Scope above the List Records action so I could drag the List records in first than the For each loop next

This concept will help us in the following tips

4. Parallel Branches

All Flows run from top to bottom in a single order fashion. If we split the actions to run side by side (parallel) This would drastically improve performance.
In this scenario I have Two(2) CDS List records, and Two(2) Apply to each loops

List Records – Users
Apply to each – To Append(add) all First names into a single variable
List Records – Accounts
Apply to each – To Append(add) all Account names to a single variable

Here is what the Flow looks like:

Running the Flow, we can see it takes about 4 minutes

Before we create a parallel branch we first must put the actions inside a Scope, this is to allow us to drag the actions around without getting the

This action cannot be dragged above actions it depends on. Error

Refer to Tip# 3 for details on Scopes

Now lets have these 2 different Scopes run in parallel branches
First we want to click the ‘+’ icon where we want to add the branch, next click Add parallel branch

In this example, I am adding a parallel branch above both Scopes

Our screen will look like this:

Next we need to Click and Drag one of the scopes to the new branch

Once the Scope is in the branch we can click the X on the Choose an action tab

NOTE: If you are adding a Parallel branch in the middle of a Flow, you might encounter a strange scenario where the new branch goes nowhere, or a dead-end. Please refer to my Blog on the Community forums to solve this:
https://powerusers.microsoft.com/t5/Power-Automate-Community-Blog/Adding-a-New-Parallel-Branch-Goes-Nowhere/ba-p/514676

Now lets run thew Flow again:
As the picture below shows, the Flow now only takes 2 minutes to run, cutting our run time by half, that’s insane!

Imagine our run normally taking 30 minutes, now only taking 15, just from a simple step

Tip# 5 will make our Flow run even faster!!

5. Concurrency

What is it? By default loops run one after another. Concurrency can make loops run in parallel.
To better understand this, we can think about a grocery store. In this scenario:

People = Value that is going into Apply to each loop
Lanes/Cashier = Concurrency Control Number


There are 20 people waiting in line at the store. There is 1 lane/cashier open. Since the cashier can only take one person at a time, this process can be lengthy.
Now with Concurrency turned on, things are a bit different. Lets say we set Concurrency to 5. This means 5 lanes/cashiers will be open. This is great! But there is a catch..

When Concurrency is enabled, there is no more line. All 20 people are processed randomly.

Concurrency can be applied to all Apply to each loops — As well as Triggers!

To enable Concurrency:

First, click the 3 dots on the Apply to each action
Next, click settings

Next, choose the value for Concurrency and click Done

For this Demo, I am setting Concurrency to 50. Please be aware of API limit calls and 429 errors. If you get these errors while flow is running. Decrease the Degree of Parallelism

Now lets see this in action!
I set Concurrency to 50 on both my Apply to each loops from the last Tip.
As a recap, the last time we ran the Flow, it took 2 minutes to run.

Results: About 5 seconds!

The Run time is about 5 Seconds. Since we used a Parallel branch the total run time is the longest duration of our Parallel branches

This drastically improves performance.

Conclusion / Key Take Notes

  1. Use a Compose action to check values and outputs, that you normally cannot see, Like in a If Condition
  2. Compose actions can store almost any data type. When in doubt.. Use a Compose
  3. When using expressions, try using them in a Compose, this can make troubleshooting much easier
  4. Always use meaningful names for all your actions. Doing this will save loads of time later on, when needing to use dynamic content
  5. Comment, comment, and more comments. All actions allow for comments. This will help support teams troubleshoot your Flow, as well as your future self, if you have to make any updates later on
  6. When using expressions, copy the expression and paste into the actions comments section.
  7. Use Scopes to group actions together.
  8. To speed up performance, use parallel branches to enable actions to run side by side
  9. Enable Concurrency control on Apply to each loops to drastically increase performance
  10. Remember enabling Concurrency control randomizes the order the loop iterations run in. So if you’re expecting a certain order processing to happen, do not enable

These are some of the tips and tricks I wish I knew sooner. I hope at least one of these tips and ticks have helped someone. Thanks for reading!