Compare two array objects

[Garima]

I am looking for a way to compare two array objects. Both the objects have email address and I want only those email address that are unique to the second one.

For example -

Array1 - [ test@abc.com, test1@abc.com, new@xyz.com]

Array2 - [ test@abc.com, test1@abc.com, test2@xyz.com]

What I want is -> test2@xyz.com. 

Basically opposite of intersection operation.

If not with array, is it possible to get this using string? 

[v-xida-msft]

Hi @Garima,

Do you want to compare two array objects and find the unique elements within the second array?

I have made a test on my side and please take a try with the following workaround:

• Add a proper trigger, here I use Flow Button trigger.
• Add a Variables-> "Initialize variable" action, Name set to Array1, Type set to Array and Value set to following formula:

["test@abc.com","test1@abc.com"," new@xyz.com"]

• Add a Variables-> "Initialize variable 2" action, Name set to Array2, Type set to Array and Value set to following formula:

["test@abc.com","test1@abc.com","test2@xyz.com"]

• Add a Variables-> "Initialize variable 3" action, Name set to UniqueEmails, Type set to Array and Value set to empty.
• Add a "Apply to each" action, input parameter set to Array2 variable. Within "Apply to each" action, add a Condition, click "Edit in advanced mode", type the following formula:

@contains(variables('Array1'), item())

Within "If/no" branch of Condition, add a "Append to array variable" action, Name set to UniqueEmails variable, Value set to following formula:

item()

• Under "Apply to each" action, add a "Compose" action, Inputs field set to UniqueEmails variable.

Image reference:

The flow works successfully as below:

More details about using expression in flow actions, please check the following article:

Use expression in flow actions

If you want to compare two strings (compare characters within two strings), I afraid that there is no direct way to achieve your needs in Microsoft Flow currently.

Best regards,

Kris

[GamerTuku]

This is awesome! thank you. 

Question: what if i wanted to find unique records based on a difference in a single field? 

for example

if Array1 has a "Title" Field and an "Email" field

and Array 2 has a "Title" field and an "Email" field

I want to populate ArrayUniqueEmails only where the title doesn't exist?

Can this be done? 

[gdavenport]

I would like to know this too

[Eliot]

Hi, @v-xida-msft , this looks great ... however there's no option to edit the condition in advanced mode. How do we get there?

EDIT -- 

Figured it out, I'm an idiot, but others may be as dumb as me.

[JE-ax]

@Garima 

Use Filter Array

Result is: [ "3" ]

[DudelerDad]

Eliot just so you know  there are others as I have been struggling with this but your simple solution should work for me.

Thanks.

[Powerplatform01]

@Garima 

You can watch this video to resolve your issue.

Also request you to please subscribe this PowerAutomate channel

https://youtu.be/OIIjOy-p-UE

[nitinkhubani]

I actually found a better way for comparing two arrays without Apply to Each loop

equals(length(intersection(variables('Array 1'),variables('Array 2'))),length(variables('Array 1')))

[gdavenport]

Nicely done nitinkhubani

[JE-ax]

But then you only know if the lengths of the arrays are different. But you still need the values from Array2.

[kbig]

True MVP! This is the fastest way to compare two arrays and return the difference from one of them.

You can repeat the function and swap out the sources in the From and Contains parameters to return the difference for both. 

I must have seen a dozen different solutions from Microsoft support staff that could not provide this elegant formula. THANK YOU!

[KashifZH]

Great, thanks for your reply!

I had to compare a property after parsing JSON and you're solution using "contains" helped me compare items between arrays.

[asdfaf4]

I don't fully understand the recommendation solution. Can someone kindly provide additional clarity to fully compare the content of 2 arrays, not just comparing the length?

[Chriddle]

That doesn't check for equality.

At a minimum, you should check that the length of the intersection is also equal to the length of Array2.

And there must be no duplicates in the arrays.

Furthermore, the order of the items is not considered.

What about equals(array1, array2) 😉

[SteveCochrane]

Many thanks! My two arrays contain the same structure, but from two different sources, and the "Filter array" worked perfectly for me.