Filter dropdown based on previous dropdown selection

[Tricky778]

I have a PowerApp using a SharePoint List. Let's call the list 'TestList'. 

One of the SharePoint columns in this list is called 'Legal Entity' and contains a list of legal entity's in the format (entity code and name):

1001 Finance

1002 PLC

1003 IT

1004 HR etc.

Another SharePoint column is called 'Site' and contains a list of sites in the format (site name and entity code).

Some sites will have more than one entity present:

Birmingham 1001

Liverpool 1001

Manchester 1001

Birmingham 1002

London 1002

Edinburgh 1003 etc.

The entity code is always 4 numbers. 

I'm trying to think of a way whereby if the user selects '1001 Finance' in dropdown1, dropdown2 then filters (based on the dropdown1 selection) to only show items which have '1001 as the last 4 digits'.

My thoughts are that this should be possible by using the Left / Right functions as the entity codes are the first 4 digits from the left in dropdown1 and the last 4 digits on the right of dropdown2.

For example if I throw a basic text label on the screen with the syntax:

Left(dropdown1.Selected.value, 4) and then I select '1001 Finance' in dropdown1 it correctly shows 1001.

If I alter the syntax in the text label to the following:

Right(dropdown2.Selected.Value, 4) it will correctly show '1001' if I select 'Birmingham 1001' in dropdown2.

But I'm stuck with how I can apply the filtering using these commands / or something more appropriate. 

Just wondering if anyone's encountered something similar or has any ideas? 

[CNT]

@Tricky778 I'm showing it with collections for illustration. You can replace it with your SP lists and the corresponding columns,

[v-qiaqi-msft · Accepted solution]

Hi @Tricky778,

Do you want to filter the dropdown list from the Site column based on another Dropdown selected?

Could you please tell me that if both of the 'Legal Entity' and Site are Choice column?

From your description, I just assume that both of the 'Legal Entity' and Site are Choice column.

In my scenario, I have a Dropdown5 filled with the 'Legal Entity' by setting the Items as:

Choices(TestList.'Legal Entity')

I also have a Dropdown6 filled based on the Dropdown5 selected by setting the Items as:

Filter(Choices(TestList.Site),Right(Value,4) = Left(Dropdown5.Selected.Value,4))

Check if it could help you.

Regards,

Qi

[Tricky778]

Worked perfectly, thank you @v-qiaqi-msft, and for your input @CNT