How to Efficiently Work with Arrays Using Filter Array, Select, and Join in Power Automate

Introduction

Power Automate provides several Data Operations actions for working with arrays. Among them, Filter array, Select, and Join are commonly used to filter records, select required fields, and combine values.

Although all three actions work with arrays, each has a different purpose:

• Filter Array → Selects the required records

• Select → Selects or reshapes the required fields

• Join → Combines array values into a single text string

This article explains these three actions using a simple employee example with Demo Person 1, Demo Person 2, Demo Person 3, and Demo Person 4.

1. Filter Array

What is Filter Array?

The Filter Array action is used to return only records that match a specific condition.

Key Question

Which records do I need?

Demo Employee Data

Assume we have the following employee records:

Suppose we only need employees from the IT department.

Power Automate Action

Add:

Data Operation → Filter array

From:

value

from the Get items action.

Condition

item()?['Department'] is equal to IT

Output

When to use Filter Array

Use Filter array when you need to:

• Find records matching a condition.

• Filter SharePoint items.

• Filter employees by department.

• Filter invoices by status.

• Filter approval records.

• Remove unwanted records before the next step.

2. Select

What is Select?

The Select action is used to select specific properties from an array and create a new structure.

Key Question

Which fields do I need?

After filtering the employees, suppose we only need the Person Name and Email.

Power Automate Action

Add:

Data Operation → Select

From:

Use the output of Filter array.

Mapping

Output

[
  {
    "PersonName": "Demo Person 1",
    "Email": "[email protected]"
  },
  {
    "PersonName": "Demo Person 3",
    "Email": "[email protected]"
  }
]

The Select action has removed the unnecessary ID and Department fields.

When to use Select

Use Select when you need to:

• Keep only required fields.

• Rename fields.

• Create a new array structure.

• Prepare data for another Power Automate action.

• Reduce unnecessary information from an array.

3. Join

What is Join?

The Join action combines values from an array into a single text string using a delimiter.

Key Question

How do I combine values into text?

For example, after filtering the IT employees, we may want their names in one text string.

Example Input

Demo Person 1
Demo Person 3

Power Automate Action

Add:

Data Operation → Join

From:

The required array values.

Join with:

,

Output

Demo Person 1, Demo Person 3

You can also use other delimiters, such as:

;

Output:

Demo Person 1; Demo Person 3

When to use Join

Use Join when you need to:

• Create a comma-separated list.

• Create a semicolon-separated list.

• Combine email addresses.

• Create readable text from an array.

• Prepare a value for an email or notification.

Real-World Example

Suppose we want to send an email notification to all IT employees.

The flow can be designed as:

Get Items
     ↓
Filter Array
Department = IT
     ↓
Select
Person Name / Email
     ↓
Join
Combine Email Addresses
     ↓
Send Email

Step 1 – Get Items

Use the SharePoint Get items action to retrieve employee records.

Step 2 – Filter Array

Filter employees where:

Department = IT

Result:

Demo Person 1
Demo Person 3

Step 3 – Select

Select only the Email field:

item()?['Email']

Result:

[email protected]
[email protected]

Step 4 – Join

Use a comma as the delimiter.

Result:

[email protected],[email protected]

Step 5 – Send Email

Use the resulting email list in the appropriate recipient field of the email action.

Filter Array vs Select vs Join

Easy Way to Remember

Filter Array → Choose Records

Select → Choose Fields

Join → Combine Values

Common Mistakes

1. Using Select to filter records

If you need to find only IT employees, use Filter Array, not Select.

Filter Array → Department = IT

2. Using Filter Array when you only need specific fields

If you already have the correct records and only need Person Name and Email, use Select.

3. Using Join directly on complex objects

Join is intended to combine values into text. If your array contains complete objects, first use Select to extract the required value.

4. Not checking the output

Always check the output of each action in Run history before configuring the next action.

For example:

Get Items
    ↓
Check Output
    ↓
Filter Array
    ↓
Check Output
    ↓
Select
    ↓
Check Output
    ↓
Join

This helps identify incorrect property names and array-format issues.

Example in an Invoice Approval Process

The same approach can be applied to an Invoice Approval solution.

For example, suppose you retrieve multiple approval records and need to notify pending approvers:

Get Approval Items
        ↓
Filter Array
Approval Status = Pending
        ↓
Select
Approver Email
        ↓
Join
Combine Email Addresses
        ↓
Send Notification Email

For example, the result could be:

[email protected],[email protected]

This allows the flow to process the required records without unnecessarily looping through every item.

Key Takeaway

Filter Array, Select, and Join have different responsibilities:

Filter Array = Choose the records
Select       = Choose the fields
Join         = Combine values into text

They can also be used together:

Get Data
   ↓
Filter Array
   ↓
Select
   ↓
Join
   ↓
Use Final Output

Understanding these three Data Operations makes Power Automate flows cleaner, easier to maintain, and more efficient.

Conclusion

Filter Array is useful when you need specific records, Select is useful when you need specific fields or a different data structure, and Join is useful when you need to convert multiple array values into a single text string.

Using Filter Array → Select → Join together is a practical pattern for many Powers Automate scenarios, including SharePoint data processing, employee notifications, invoice approvals, and email recipient generation.