The LastN function in Power Apps is used to retrieve the last N records from a table or collection. This function is useful when you need to display or process the most recent entries in a dataset, such as the latest transactions, messages, or records.
PowerApps –LastN() function syntax
LastN(Table, NumberOfRecords)
- Table: The table or collection from which you want to retrieve records.
- NumberOfRecords: The number of records you want to retrieve from the end of the table.
Notes:
- Delegation: Be mindful of delegation limits when working with large datasets and ensure the data source supports delegation if necessary.
- Combining with Other Functions: Combine LastN with functions like Filter, Sort, and Search to retrieve and display the most relevant records.
- User Input Validation: Ensure that user inputs for the number of records to retrieve are valid numbers to prevent errors.
- Displaying Recent Entries: Use LastN to display the most recent entries in a collection, such as the latest messages, transactions, or updates.
PowerApps – Retrieve Last Two Records from collection
Suppose you have a collection named Products and you want to get the last two products in this collection.
- Create the Collection:
ClearCollect(Products,
Table(
{ProductID: 1, ProductName: "Laptop", Price: 1000},
{ProductID: 2, ProductName: "Tablet", Price: 500},
{ProductID: 3, ProductName: "Monitor", Price: 300}
)
);
- Retrieve the Last Two Records:
- Add a Gallery control.
- Set the Items property of the Gallery to:
This will display the last two products, "Tablet" and "Monitor".
PowerApps – Get LastN records from a Filtered Collection
Suppose you want to get the last three products that cost less than $600 from the Products collection.
ClearCollect(Products,
Table(
{ProductID: 1, ProductName: "Laptop", Price: 1000},
{ProductID: 2, ProductName: "Tablet", Price: 500},
{ProductID: 3, ProductName: "Monitor", Price: 300},
{ProductID: 4, ProductName: "Keyboard", Price: 100},
{ProductID: 5, ProductName: "Mouse", Price: 50}
)
);
- Retrieve the Last Three Records from Filtered Collection:
- Add a Gallery control.
- Set the Items property of the Gallery to:
LastN(Filter(Products, Price < 600), 3)
This will display the last three products with a price less than $600, which are "Monitor", "Keyboard", and "Mouse".
Suppose you want to allow users to specify how many records to retrieve from the Products collection.
- Add a Text Input Control:
- Insert a Text Input control named RecordCountInput.
- Retrieve the Specified Number of Records:
- Add a Gallery control.
- Set the Items property of the Gallery to:
LastN(Products, Value(RecordCountInput.Text))
This will display the number of products specified by the user in the RecordCountInput control.