Checking for duplicates in an array or list

Question

Hi 
 I want to check for duplicates in Supplier list when I am adding a new supplier. 
 I tried using this expresssion: 
 a!textField(
 label: "Supplier Name",
 value: fv!item.description,
 saveInto: fv!item.description,
 validations:
 {
 if(
 count(wherecontains(local!suppliers,index(fv!item,fv!index,{})))>1,
 "Supplier already exists",{}
)
}, 
 
 But I am getting the error -> Could not display interface. Please check definition and inputs. Interface Definition: Expression evaluation error at function a!forEach [line 39]: Error in a!forEach() expression during iteration 1: Expression evaluation error at function 'wherecontains' [line 52]: Invalid types, can only act on data of the same type (Any Type, Text) 
 I tried the methods mentioned in earlier posts but not able to fix it yet. Can someone help me? 
 
 Thanks

Mike Schmitt · Accepted Answer

It's hard to tell without knowing what the value of local!suppliers is, which apparently depends on the result of your initial query. It looks, though, as if the data rows you're getting back don't contain a ".description" property. The error message we're seeing here is the standard error message received when you try to take a dot property from a dictionary/CDT for a property it doesn't have. 
 To circumvent this, we can try to get the dot property safely by using the property() function, i.e. touniformstring(property(local!suppliers, "description", {}))

Danny Verb · Answer

You need to wrap 'local!suppliers' in the function touniformstring() which will make sure that you're acting on data of the same type

GopalK · Answer

If you are storing supplier name in fv!item.description then you should use this field only to check whether value provided by user exists in local! suppliers or not.i assume you have list of suppliers in local!suppliers then your expression should be like below, 
 WhereContains(touniformstring (local! suppliers),fv!item.description)

Mike Schmitt · Answer

also it would be "local!suppliers.description", since local!suppliers is apparently a dictionary containing a "description" field that's the target of the text field in question.

Mike Schmitt · Answer

If the dictionary is empty then the ".description" property might not evaluate correctly before an initial entry is added. 
 Also the function is "touniformstring()", not "touniform()" like you have in your code currently.

Mike Schmitt · Answer

Additionally, whereContains() requires the unique item (and/or item(s)) you're trying to find the positions of in the longer/original array, to be listed first in the function, not second. 
 And if your local!suppliers is a generic dictionary, the .description property will probably need to be typecast because whereContains() is picky about types. 
 Thus, it would be properly written like this: 
 wherecontains(
 tostring(fv!item.description),
 touniformstring(local!suppliers.description)
)

Mike Schmitt · Answer

I whipped up my own version of this real quick and it appears to be working fine. 
 a!localVariables(
 
 local!suppliers: {},
 
 a!gridLayout(
 headerCells: {
 a!gridLayoutHeaderCell(label: "Description")
 },
 
 rows: a!forEach(
 local!suppliers,
 a!gridRowLayout(
 contents: {
 a!textField(
 value: fv!item.description,
 saveInto: fv!item.description,
 validations: if(
 count(
 wherecontains(
 tostring(fv!item.description),
 touniformstring(local!suppliers.description)
 )
 ) > 1,
 "Supplier already exists",
 ""
 )
 )
 }
 )
 ),
 
 addRowLink: a!dynamicLink(
 label: "Add",
 saveInto: a!save(
 local!suppliers,
 append(
 local!suppliers,
 {
 id: 1,
 description: ""
 }
 )
 )
 )
 )
)

Checking for duplicates in an array or list

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