Create empty collection

[ck25415]

Is it possible to create an empty collection?

[caballo111]

Thanks! How did you come with this solution?
I tried with Blank(), but then couldn't do an updateif with a number (column was expecting objNull and received a Number).
I tried with Value(Blank()), but that evaluated to 0.

[ell10706]

Pure guesswork! 

[RJM07]

ClearCollect(collEmpty,{Field1:Value(""),Field2:Value("")});
Clear(collEmpty)

This works for numbers, Essentially it builds a blank collection that's expecting numbers. but because of the "" it has a blank row at the top which will stop you from patching it. So you need to clear it immediately after. This keeps the collection in play but makes it empty and ready for you to input values.

[alexotoodev]

the best way to do it is this example below;

ClearCollect(bulkUpdate,{TakenBy:(""),courseName:(""),HoursDone:Value("")})

use ("") instead of BlanK() and Value("") for number values.   I will advise against using Blank() because it gives you error when you use patch to update the values. 

[Rekokoko]

Nothing works for me:

First invocation of:

Collect(col_test; Blank());
ClearCollect(col_test; Blank());

always returns error. that col_test is not recognized.

Sometimes reloading editor helps, sometimes you need to create collection with dummy values, clear it and it works. This is just beyond imagination how bad design / implementation this is.

[NatEvansIT]

Don't give up!

I think you just need to empty the collection once made using clear, although worth thinking about what type of data you want to collect to then clear - for example when I pull from a table that already exists, I might take a row of correctly formatted data, then clear it

ClearCollect(col_test, First(table));

Clear(col_test);

P.S. create a button to create the collection and a separate button to clear it, sometimes you need to create the collection in PowerApps first so that it knows of it and testing using with buttons usually helps work out why it is failing - I do this all the time! You can check the collection exists by looking at the collection in the left hand menu of PowerApps

[Rekokoko]

@NatEvansIT thanks, but such hacking just to initialize a collection defeats whole purpose of low-code approach. All gains I get at start goes away then you need to fight technology like this to do anything slightly complex than tutorials.

Other thing is that documentation clearly is misleading, in another post there's drama related to Collect which supposed to create new collection, instead it complains that it's not recognized. It's totally random... sad_pepe_face

[Snekithan]

I am setting the table from UntypedObject (Json) from HTTP Response, how to set the empty table when it returns error. 

I am setting Items as 

If(!IsEmpty(varUserTable), varUserTable, ClearCollect(varUserTable, { Blank() }))

How to fix this? Any help?

[NatEvansIT]

Is it...

If(!IsEmpty(varUserTable), varUserTable, Clear(varUserTable))

?