This guide presents how to reduce a list to a single value using the Workflows Reduce card. 

• Okta Workflows

What is the Reduce card?

The Reduce card takes a list of values and reduces them to a single value.

For example, there is a list of text values:

• Milk
• Bread
• Butter
• Eggs
• Cheese

It is desired to obtain a single text value consisting of all the values from the list:

> Groceries: 
* Milk
* Bread
* Butter
* Eggs
* Cheese

It is necessary to reduce the list to a single value.
 

The solution has two flows:

1. The main flow that creates the list and calls the Reduce card
2. A helper flow that concatenates each text

Creating a list and calling the Reduce card

The main flow creates the list and calls the Reduce card:

1. The List – Construct card creates the list.
2. The List – Reduce card takes the list and runs the Helper helper flow on each item.
   • memo has an initial value of > Groceries.
   • Values from the list will be added to the initial value.
   • Item is each item value from the list
   • In the output section, the item holds the reduced value after all the items are processed.
3. The Text – Compose card displays the reduced value.

NOTE: memo field type (Text) needs to match the card’s output item field type (Text).

Helper flow to process (reduce) each list item

This is the helper flow:

The helper flow runs for each item in the list.

First run

On the first run, the memo value is:

> Groceries

and

* Milk

is appended to it.

The helper flow returns:

> Groceries
* Milk

Second run
On the second run, the memo value is:

> Groceries
* Milk

and

* Bread

is appended to it.

The helper flow returns

> Groceries
* Milk
* Break

Third run
On the third run, the memo value is:

> Groceries
* Milk
* Break

and

* Butter

is appended to it.

The helper flow returns:

> Groceries
* Milk
* Break
* Butter

Fourth run
 On the fourth run, the memo value is:

> Groceries
* Milk
* Break
* Butter

and

* Eggs

is appended to it.

The helper flow returns:

> Groceries
* Milk
* Break
* Butter
* Eggs

Fifth run
On the fifth run, the memo value is:

> Groceries
* Milk
* Break
* Butter
* Eggs

and

* Cheese

is appended to it.

The helper flow returns:

> Groceries
* Milk
* Break
* Butter
* Eggs
* Cheese

Since cheese is the last item, the Reduce card completes processing.

The last helper flow run:

This is the final result. A list of items is reduced to a single text value

> Groceries
* Milk
* Break
* Butter
* Eggs
* Cheese

Related References

• Learn the Differences Between Three Workflows List Functions: For Each, Map, and Reduce (guide, video).
• How to Reduce a List to a Single Value, 3 Examples Using List-Reduce Workflows Card (guide, video).