Concatenate a Collection of Strings (Text) into a comma-delimited string in a Flow

Question

I'm working with a product called SDocs which generates PDFs (among other things). I need to pass a comma-delimited String of "names" to generate more than one PDF at once.

The names (datatype: text) are already stored in a collection. Assuming I don't know the size of the Collection, is there a way to do this in a Flow without using Apex? I have no problem using Apex, the customer just prefers "No Code".

Answer 1

I am sure that there is more than one way to skin a cat, but here is something quick and dirty I came up with....

---

Prep

• [A] DocNamesCollection: Text Collection Variable
• [B] DocNamesList: Text Variable that is NOT a Collection
• [C] DocNamesCount: Number Variable

---

Flow

Step 1

This is just assigning "DocName01", "DocName02" and "DocName03" to DocNamesCollection for me to use in the sample Flow.

Step 2

A standard Loop through DocNamesCollection

Step 3

Add 1 to DocNamesCount

Step 4

Simple Decision element to check if DocNamesCount is greater than 1

First time through it will go straight to Step 5; after that, it should go through Step 6

Step 5

Add the current Loop item value to DocNamesList:

Step 6

Add a comma to DocNamesList:

---

Results

From the Flow debug:

---

After you exit the loop, you should be able to replace what you have highlighted in your question with the name of the Text List Variable (DocNamesList in the sample).

As stated earlier, there are multiple ways you could do it. If your original Collection of doc names is a Record Collection, you can grab the count directly. If you "manually" build your Collection of doc names earlier in the Flow, you could instead use the above loop, skip building a Collection, and instead directly add on to a non-Collection variable as shown.

Answer 2

This can be done with a simple flow formula: If your original source data is in a Text Collection named DocNamesCollection with the content...

Payload1
Payload2
Payload3
Payload4

...just create a flow formula DocNamesCollectionCsv of type text that reads

{!DocNamesCollection}

This formula will result to

[Payload1,Payload2,Payload3,Payload4]

Apparently you want to get rid of the [], then change the above text formula to

MID({!DocNamesCollection}, 2, LEN({!DocNamesCollection}) - 2)

which will deliver the desired result of

Payload1,Payload2,Payload3,Payload4

If you want to count the number of elements in your collection, just define a Number variable DocNamesCount and use it in an assignment element as follows:

Variable=DocNamesCount | Operator=Equals Count | Value={!DocNamesCollection}

If your source collection happens to come from a record collection, e.g. build a list from Account.Name out of a GetRecords on Account, you can use the Transform element to convert the Account collection into a text collection and do same as above.

Important note:

• This will fail if your payload contains " as string delimiters will not be escaped.
• This will fail if your payload contains comma , as the approach cannot distinguish between payload comma and list comma.

If you need to deal with such special cases and/or want to have the string delimiter or the field delimiter configurable, I suggest my BLOG post with a detailed explanation on how to enhance the formulas to achieve this: How to Concatenate a Collection of Strings to a Comma-Delimited String in Salesforce Flow