cancel
Showing results for 
Search instead for 
Did you mean: 
Reply
Anonymous
Not applicable

Performing a FOR loop in PowerApps

Until FOR loops are added in PowerApps, I have a workaround that I've been using and it's really come in handy.

I start by adding a collection in my App's OnStart property (I'll show at the end how to do this in Flow, which I prefer).

I've attached a template for this from 0-1000 (For.txt at the bottom)

 

ClearCollect(Loop,
{Index:0},
{Index:1},
{Index:2},
{Index:3},
...
{Index:100}
)

 

 You can now perform a FOR loop by filtering this collection. For example, if I want to get a collection of dates that are 7 days from a selected date, I can do this:

 

Clear(NextDates);
ForAll(Filter(Loop,Index<=7),
Collect(NextDates,
 {
     Date:DateAdd(DatePicker1.SelectedDate,Index,Days),
     DaysSincePickedDate:Index,
     DayOfWeek:Weekday(DateAdd(DatePicker1.SelectedDate,Index,Days))
}
))

 

I get this result:
2020-01-14 08_52_38-Window.png\

Remember that the numbers don't have to be hardcoded. You can use CountRows(),a numeric input, or any other integer to drive this code.

The shell of the FOR loop looks like this:

 

Set(i,0);
ForAll(
Filter(Loop,Index<=7,Index>=i),
//Code
)

 

This would be the equivalent to something like this:

 

for (i = 0; i <= 7; i++)
{
 //code
}

 

To clean up the Loop collection, I use Flow. Here's what that solution looks like:

for.png

I can now use this code to get my Loop collection (I like to rename the column to Index, since Value is the generic term from Flow)

 

ClearCollect(Loop,RenameColumns(For.Run(1000),"Value","Index"));

 

That will return a collection of 1000 rows without all the manual coding! This Flow is pretty slow, so you can also setup this logic to only load it once for each user (this saves the collection to memory on mobile):

 

LoadData(Loop,"Loop", true );
If(CountRows(Loop)=0,
  ClearCollect(Loop,RenameColumns(For.Run(100),"Value","Index"));
  SaveData(Loop,"Loop")
  )

 

2 ACCEPTED SOLUTIONS

Accepted Solutions
Anonymous
Not applicable

CarlosFigueira
Power Apps
Power Apps

[Updated on 2022-11-03] This is an old reply but I see that it's still getting views, so I decided to update it with the Sequence function, which was added over a year ago (not sure exactly when) which can make it much easier (no need to define large collections):

ForAll(
    RenameColumns(Sequence(CountRows(MyColl)), "Value", "Index"),
    // Code
)

 

[Original reply]

This is a pretty good workaround to the lack of a 'for' construct in PowerApps. I've been using something similar, and those are some things that you can do to make your code a little faster and/or smaller:

  • To create the 'Loop' collection, you can use the abbreviated array syntax ([...]), and rename the column to 'Index':
    • ClearCollect(LoopMaster(RenameColumns([0,1,2,3,4,5,6,7,8,9,...,999],"Value","Index"))
      • Attached a file with the expression to create that loop master
    • This is pretty fast; I have apps with collections like this created with 5000 items, no noticeable performance impact (I even measured in a few apps, and the time it takes is usually around 10-20ms
  • Once you have this (large) loop master collection, you can use the FirstN function to create a loop collection of the size that you want. For example, if you want to loop over a collection MyColl, you can use this expression:

 

 

ForAll(
    FirstN(LoopMaster, CountRows(MyColl)),
    // Code
)

 

 

  • If you don't want to have a very large expression, you can trade off code length by performance. The expression below is equivalent to the one above, but in my tests it takes ~1-5 seconds to execute:

 

 

ClearCollect(LoopMaster,{Index:0}); Clear(LoopMaster);
ForAll(
    RenameColumns([0,1,2,3,4,5,6,7,8,9], "Value", "Hundreds"),
    ForAll(
        RenameColumns([0,1,2,3,4,5,6,7,8,9], "Value", "Tens"),
        ForAll(
            RenameColumns([0,1,2,3,4,5,6,7,8,9], "Value", "Ones"),
            Collect(LoopMaster, {Index: Hundreds * 100 + Tens * 10 + Ones}))))

 

 

  • If you want to create your own loop, using the FirstN function will probably be faster than filtering - especially if your 'master loop' is a large expression. For example, this is equivalent to your example:

 

 

Clear(NextDates);
ForAll(
    FirstN(LoopMaster, 8),
    Collect(
        NextDates,
        {
            Date:DateAdd(DatePicker1.SelectedDate,Index,Days),
            DaysSincePickedDate:Index,
            DayOfWeek:Weekday(DateAdd(DatePicker1.SelectedDate,Index,Days))
        }))

 

 

  • One more performance hint: if you're using ForAll to add elements to an empty collection using the index, you may want to look into using ClearCollect and the AddColumns function to add the elements, followed by the RemoveColumns to remove the index (if you want to do so). In my empirical testing I've found that this is 5-10 times faster than using ForAll (ForAll is not a very performant function). The example above would look like this:

 

 

ClearCollect(
    NextDates,
    DropColumns(
        AddColumns(
            FirstN(LoopMaster, 8),
            "Date", DateAdd(DatePicker1.SelectedDate,Index,Days),
            "DaysSincePickedDate", Index,
            "DayOfWeek", Weekday(DateAdd(DatePicker1.SelectedDate,Index,Days))),
        "Index"))

 

 

 

Hope this helps, and thank you for sharing your ideas!

View solution in original post

19 REPLIES 19
Anonymous
Not applicable

Marking solution
CarlosFigueira
Power Apps
Power Apps

[Updated on 2022-11-03] This is an old reply but I see that it's still getting views, so I decided to update it with the Sequence function, which was added over a year ago (not sure exactly when) which can make it much easier (no need to define large collections):

ForAll(
    RenameColumns(Sequence(CountRows(MyColl)), "Value", "Index"),
    // Code
)

 

[Original reply]

This is a pretty good workaround to the lack of a 'for' construct in PowerApps. I've been using something similar, and those are some things that you can do to make your code a little faster and/or smaller:

  • To create the 'Loop' collection, you can use the abbreviated array syntax ([...]), and rename the column to 'Index':
    • ClearCollect(LoopMaster(RenameColumns([0,1,2,3,4,5,6,7,8,9,...,999],"Value","Index"))
      • Attached a file with the expression to create that loop master
    • This is pretty fast; I have apps with collections like this created with 5000 items, no noticeable performance impact (I even measured in a few apps, and the time it takes is usually around 10-20ms
  • Once you have this (large) loop master collection, you can use the FirstN function to create a loop collection of the size that you want. For example, if you want to loop over a collection MyColl, you can use this expression:

 

 

ForAll(
    FirstN(LoopMaster, CountRows(MyColl)),
    // Code
)

 

 

  • If you don't want to have a very large expression, you can trade off code length by performance. The expression below is equivalent to the one above, but in my tests it takes ~1-5 seconds to execute:

 

 

ClearCollect(LoopMaster,{Index:0}); Clear(LoopMaster);
ForAll(
    RenameColumns([0,1,2,3,4,5,6,7,8,9], "Value", "Hundreds"),
    ForAll(
        RenameColumns([0,1,2,3,4,5,6,7,8,9], "Value", "Tens"),
        ForAll(
            RenameColumns([0,1,2,3,4,5,6,7,8,9], "Value", "Ones"),
            Collect(LoopMaster, {Index: Hundreds * 100 + Tens * 10 + Ones}))))

 

 

  • If you want to create your own loop, using the FirstN function will probably be faster than filtering - especially if your 'master loop' is a large expression. For example, this is equivalent to your example:

 

 

Clear(NextDates);
ForAll(
    FirstN(LoopMaster, 8),
    Collect(
        NextDates,
        {
            Date:DateAdd(DatePicker1.SelectedDate,Index,Days),
            DaysSincePickedDate:Index,
            DayOfWeek:Weekday(DateAdd(DatePicker1.SelectedDate,Index,Days))
        }))

 

 

  • One more performance hint: if you're using ForAll to add elements to an empty collection using the index, you may want to look into using ClearCollect and the AddColumns function to add the elements, followed by the RemoveColumns to remove the index (if you want to do so). In my empirical testing I've found that this is 5-10 times faster than using ForAll (ForAll is not a very performant function). The example above would look like this:

 

 

ClearCollect(
    NextDates,
    DropColumns(
        AddColumns(
            FirstN(LoopMaster, 8),
            "Date", DateAdd(DatePicker1.SelectedDate,Index,Days),
            "DaysSincePickedDate", Index,
            "DayOfWeek", Weekday(DateAdd(DatePicker1.SelectedDate,Index,Days))),
        "Index"))

 

 

 

Hope this helps, and thank you for sharing your ideas!

Anonymous
Not applicable

That's an awesome piece of syntax I didn't know about! I also didn't even think to use FirstN().
Thank you for sharing!

Hey @CarlosFigueira,

 

this is such a useful tip, but I can't for the life of me get the RenameColumns([0,1,2,3,4,5,6,7,8,9,...,999] to work.  I always get a squiggle under the ...  "invalid use of '.'"

 

Is there some preview feature I need to turn on to get this?

 

Thanks

Craig

Anonymous
Not applicable

The '...' is just to denote numbers between 9 and 999, it's not actually part of the formula.

Seriously?  So you have to type in all 1000 numbers? (or script out somewhere else and paste in)

 

There has to be a better way!

 

Anonymous
Not applicable

There are a handful of other ways, but typing it out is the fastest (to process, that is). You could setup an excel document with maxed out rows of consecutive integers and use that, which would probably be the most efficient.

Anonymous
Not applicable

You don't need 1000 "numbers" you need 1000 rows. It can be anything. I just did this:

 

Collect(aLongTable, [" ", " ", " ", " ",

Then copy and pasted:

" ", " ", " ", " ",

to get

Collect(aLongTable, [" ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ",

Then copy and paste 

" ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ", " ",

etc...

 

 

Took me about 30 seconds to make a table of 1000's of rows. Now you can use this to run your ForAll on your FirstN(aLongTable, NumberOfLoopsYouWant)

 

It's not exactly elegant and I still don't know a great way to increment a variable inside a ForAll but I'm sure there's a workaround for that too.

 

Yeah, I get that, but still, YUCK!

 

The value of putting numbers in the rows is that you can then compare and use partial ranges to get subsets of values - smaller numbers of items.

Helpful resources

Announcements

Tuesday Tip | How to Report Spam in Our Community

It's time for another TUESDAY TIPS, your weekly connection with the most insightful tips and tricks that empower both newcomers and veterans in the Power Platform Community! Every Tuesday, we bring you a curated selection of the finest advice, distilled from the resources and tools in the Community. Whether you’re a seasoned member or just getting started, Tuesday Tips are the perfect compass guiding you across the dynamic landscape of the Power Platform Community.   As our community family expands each week, we revisit our essential tools, tips, and tricks to ensure you’re well-versed in the community’s pulse. Keep an eye on the News & Announcements for your weekly Tuesday Tips—you never know what you may learn!   Today's Tip: How to Report Spam in Our Community We strive to maintain a professional and helpful community, and part of that effort involves keeping our platform free of spam. If you encounter a post that you believe is spam, please follow these steps to report it: Locate the Post: Find the post in question within the community.Kebab Menu: Click on the "Kebab" menu | 3 Dots, on the top right of the post.Report Inappropriate Content: Select "Report Inappropriate Content" from the menu.Submit Report: Fill out any necessary details on the form and submit your report.   Our community team will review the report and take appropriate action to ensure our community remains a valuable resource for everyone.   Thank you for helping us keep the community clean and useful!

Tuesday Tip | How to Get Community Support

It's time for another Tuesday Tip, your weekly connection with the most insightful tips and tricks that empower both newcomers and veterans in the Power Platform Community! Every Tuesday, we bring you a curated selection of the finest advice, distilled from the resources and tools in the Community. Whether you’re a seasoned member or just getting started, Tuesday Tips are the perfect compass guiding you across the dynamic landscape of the Power Platform Community.       This Week: All About Community Support Whether you're a seasoned community veteran or just getting started, you may need a bit of help from time to time! If you need to share feedback with the Community Engagement team about the community or are looking for ways we can assist you with user groups, events, or something else, Community Support is the place to start.   Community Support is part of every one of our communities, accessible to all our community members.   Within each community's Community Support page, you'll find three distinct areas, each with a different focus to help you when you need support from us most. Power Apps: https://powerusers.microsoft.com/t5/Community-Support/ct-p/pa_community_support Power Automate: https://powerusers.microsoft.com/t5/Community-Support/ct-p/mpa_community_support Power Pages: https://powerusers.microsoft.com/t5/Community-Support/ct-p/mpp_community_support Copilot Studio: https://powerusers.microsoft.com/t5/Community-Support/ct-p/pva_community-support   Community Support Form If you need more assistance, you can reach out to the Community Team via the Community support form. Choose the type of support you require and fill in the form accordingly. We will respond to you promptly.    Thank you for being an active part of our community. Your contributions make a difference!   Best Regards, The Community Management Team

Community Roundup: A Look Back at Our Last 10 Tuesday Tips

As we continue to grow and learn together, it's important to reflect on the valuable insights we've shared. For today's #TuesdayTip, we're excited to take a moment to look back at the last 10 tips we've shared in case you missed any or want to revisit them. Thanks for your incredible support for this series--we're so glad it was able to help so many of you navigate your community experience!   Getting Started in the Community An overview of everything you need to know about navigating the community on one page!  Community Links: ○ Power Apps ○ Power Automate  ○ Power Pages  ○ Copilot Studio    Community Ranks and YOU Have you ever wondered how your fellow community members ascend the ranks within our community? We explain everything about ranks and how to achieve points so you can climb up in the rankings! Community Links: ○ Power Apps ○ Power Automate  ○ Power Pages  ○ Copilot Studio    Powering Up Your Community Profile Your Community User Profile is how the Community knows you--so it's essential that it works the way you need it to! From changing your username to updating contact information, this Knowledge Base Article is your best resource for powering up your profile. Community Links: ○ Power Apps ○ Power Automate  ○ Power Pages  ○ Copilot Studio    Community Blogs--A Great Place to Start There's so much you'll discover in the Community Blogs, and we hope you'll check them out today!  Community Links: ○ Power Apps ○ Power Automate  ○ Power Pages  ○ Copilot Studio    Unlocking Community Achievements and Earning Badges Across the Communities, you'll see badges on users profile that recognize and reward their engagement and contributions. Check out some details on Community badges--and find out more in the detailed link at the end of the article! Community Links: ○ Power Apps  ○ Power Automate  ○ Power Pages  ○ Copilot Studio    Blogging in the Community Interested in blogging? Everything you need to know on writing blogs in our four communities! Get started blogging across the Power Platform communities today! Community Links: ○ Power Apps  ○ Power Automate  ○ Power Pages  ○ Copilot Studio   Subscriptions & Notifications We don't want you to miss a thing in the community! Read all about how to subscribe to sections of our forums and how to setup your notifications! Community Links: ○ Power Apps  ○ Power Automate  ○ Power Pages  ○ Copilot Studio   Getting Started with Private Messages & Macros Do you want to enhance your communication in the Community and streamline your interactions? One of the best ways to do this is to ensure you are using Private Messaging--and the ever-handy macros that are available to you as a Community member! Community Links: ○ Power Apps  ○ Power Automate  ○ Power Pages  ○ Copilot Studio   Community User Groups Learn everything about being part of, starting, or leading a User Group in the Power Platform Community. Community Links: ○ Power Apps  ○ Power Automate  ○ Power Pages  ○ Copilot Studio   Update Your Community Profile Today! Keep your community profile up to date which is essential for staying connected and engaged with the community. Community Links: ○ Power Apps  ○ Power Automate  ○ Power Pages  ○ Copilot Studio   Thank you for being an integral part of our journey.   Here's to many more Tuesday Tips as we pave the way for a brighter, more connected future! As always, watch the News & Announcements for the next set of tips, coming soon!

Hear what's next for the Power Up Program

Hear from Principal Program Manager, Dimpi Gandhi, to discover the latest enhancements to the Microsoft #PowerUpProgram, including a new accelerated video-based curriculum crafted with the expertise of Microsoft MVPs, Rory Neary and Charlie Phipps-Bennett. If you’d like to hear what’s coming next, click the link below to sign up today! https://aka.ms/PowerUp  

Tuesday Tip: Community User Groups

It's time for another TUESDAY TIPS, your weekly connection with the most insightful tips and tricks that empower both newcomers and veterans in the Power Platform Community! Every Tuesday, we bring you a curated selection of the finest advice, distilled from the resources and tools in the Community. Whether you’re a seasoned member or just getting started, Tuesday Tips are the perfect compass guiding you across the dynamic landscape of the Power Platform Community.   As our community family expands each week, we revisit our essential tools, tips, and tricks to ensure you’re well-versed in the community’s pulse. Keep an eye on the News & Announcements for your weekly Tuesday Tips—you never know what you may learn!   Today's Tip: Community User Groups and YOU Being part of, starting, or leading a User Group can have many great benefits for our community members who want to learn, share, and connect with others who are interested in the Microsoft Power Platform and the low-code revolution.   When you are part of a User Group, you discover amazing connections, learn incredible things, and build your skills. Some User Groups work in the virtual space, but many meet in physical locations, meaning you have several options when it comes to building community with people who are learning and growing together!   Some of the benefits of our Community User Groups are: Network with like-minded peers and product experts, and get in front of potential employers and clients.Learn from industry experts and influencers and make your own solutions more successful.Access exclusive community space, resources, tools, and support from Microsoft.Collaborate on projects, share best practices, and empower each other. These are just a few of the reasons why our community members love their User Groups. Don't wait. Get involved with (or maybe even start) a User Group today--just follow the tips below to get started.For current or new User Group leaders, all the information you need is here: User Group Leader Get Started GuideOnce you've kicked off your User Group, find the resources you need:  Community User Group ExperienceHave questions about our Community User Groups? Let us know! We are here to help you!

Super User of the Month | Ahmed Salih

We're thrilled to announce that Ahmed Salih is our Super User of the Month for April 2024. Ahmed has been one of our most active Super Users this year--in fact, he kicked off the year in our Community with this great video reminder of why being a Super User has been so important to him!   Ahmed is the Senior Power Platform Architect at Saint Jude's Children's Research Hospital in Memphis. He's been a Super User for two seasons and is also a Microsoft MVP! He's celebrating his 3rd year being active in the Community--and he's received more than 500 kudos while authoring nearly 300 solutions. Ahmed's contributions to the Super User in Training program has been invaluable, with his most recent session with SUIT highlighting an incredible amount of best practices and tips that have helped him achieve his success.   Ahmed's infectious enthusiasm and boundless energy are a key reason why so many Community members appreciate how he brings his personality--and expertise--to every interaction. With all the solutions he provides, his willingness to help the Community learn more about Power Platform, and his sheer joy in life, we are pleased to celebrate Ahmed and all his contributions! You can find him in the Community and on LinkedIn. Congratulations, Ahmed--thank you for being a SUPER user!  

Top Solution Authors
Top Kudoed Authors
Users online (5,336)