Android Question IN OPERATORE LIKE SQL

Gianni Sassanelli · Jul 27, 2018

Does b4a support in operator like SQL IN OPERATOR?

for Example:

B4X:

If RoleName in ( "Val1",  "Val2" ,"Val2" ) Then
       'Go
End If

Instead of:

B4X:

If RoleName = "Val1" Or RoleName = "Val2" Or RoleName = "Val2" Then
       'Go
End If

thanks

Mahares · Jul 27, 2018

Gianni Sassanelli said:
If RoleName in ( "Val1", "Val2" ,"Val2" ) Then
'Go
End If

You can do this:

B4X:

Dim RoleName As String
    Select RoleName
        Case "Val1",  "Val2" ,"Val3"
            'do something
            Log("my choice")
        Case Else
            'do something else
            Log("not my choice")
    End Select

LucaMs · Jul 27, 2018

Use a List.

B4X:

Dim lstValues As List
lstValues.Initialize2(Array As String("Val1", "Val2", "Val3"))
If lstValues.IndexOf("Val2") <> - 1 Then
' ...     
End If

Maps also can be used:
If mapValues.ContainsKey...

Mahares · Jul 27, 2018

LucaMs said:
Dim lstValues As List
lstValues.Initialize2(Array As String("Val1", "Val2", "Val3"))
If lstValues.IndexOf("Val2") <> - 1 Then
' ...
End If

I do not think your solution is correct because he is looking for more than just Val2. He is looking for Val1 or Val2 or val3

LucaMs · Jul 27, 2018

Mahares said:
I do not think your solution is correct because he is looking for more than just Val2. He is looking for Val1 or Val2 or val3

???

I wrote:
If lstValues.IndexOf("Val2") <> - 1 Then

but, of course, he can write:
If lstValues.IndexOf(RoleName) <> - 1 Then

getting the same of:

Gianni Sassanelli said:
If RoleName in ( "Val1", "Val2" ,"Val2" ) Then

or:

Gianni Sassanelli said:
If RoleName = "Val1" Or RoleName = "Val2" Or RoleName = "Val2" Then

Erel · Jul 29, 2018

Yes:

B4X:

    If IsIn("Val1", Array("Val1", "Val2", "Val3")) Then
       Log("Yes")
   End If

Sub IsIn(value As String, items As List) As Boolean
   Return items.IndexOf(value) > -1
End Sub

LucaMs · Jul 29, 2018

or:

B4X:

Sub IsIn(value As Object, items As List) As Boolean
   Return items.IndexOf(value) > -1
End Sub

It should work even with objects (even with instances of our classes or of custom types).

Mahares · Jul 29, 2018

Erel said:
If IsIn("Val1", Array("Val1", "Val2", "Val3")) Then
Log("Yes")
End If

When you use the IN operator in SQLite, you use a code like this:

B4X:

curs=Starter.SQL1.ExecQuery2("SELECT  * FROM tblVehicles WHERE make =? OR make=? OR make=? ORDER BY Make", _
    Array As String("Val1","Val2","Val3") )

or this code:

B4X:

curs=Starter.SQL1.ExecQuery2("SELECT  * FROM tblVehicles WHERE make IN (?,?,?) ORDER BY Make", _
    Array As String("Val1","Val2","Val3") )

But @Erel and @LucaMs are presenting only one value: Val1. Do you have to run your function for each of Val1, Val2 and Val3. I still do not see the logic behind your code when the thread question is looking for any of the 3 values. Please explain.

LucaMs · Jul 29, 2018

The question was:

Gianni Sassanelli said:
Does b4a support in operator like SQL IN OPERATOR?

"Does b4a support", which means: "is there a function similar to...?"

The "in" SQL (not SQLite operator) is:

So, the "b4a equivalent function" is exactly what Erel wrote (just after my great suggestion )

LucaMs · Jul 29, 2018

Mahares said:
But @Erel and @LucaMs are presenting only one value: Val1.

Maybe I can explain better what I mean so:

Mahares said:
curs=Starter.SQL1.ExecQuery2("SELECT * FROM tblVehicles WHERE make IN (?,?,?) ORDER BY Make", _
Array As String("Val1","Val2","Val3") )

You also are comparing just one value, here: the current value of "make" (or, better, the value of "make" of the "current" (each) record.

Mahares · Jul 29, 2018

LucaMs said:
You also are comparing just one value, here: the current value of "make"

Your statement is true, but the value can be any one of; "Val1", "Val2", or "Val3". Do you have to run your function for each of Val1, Val2 and Val3.
Does your function need to run this code 3 times:

B4X:

If IsIn("Val1", Array("Val1", "Val2", "Val3")) Then
       Log("Yes")
   End If
If IsIn("Val2", Array("Val1", "Val2", "Val3")) Then
       Log("Yes")
   End If
If IsIn("Val3", Array("Val1", "Val2", "Val3")) Then
       Log("Yes")
   End If

Perhaps it is best to wait and see what the creator of the thread intended to mean. If he is in tune with yours and Erel's solution, I will stand corrected.

LucaMs · Jul 29, 2018

Mahares said:
Your statement is true, but the value can be any one of; "Val1", "Val2", or "Val3". Do you have to run your function for each of Val1, Val2 and Val3.
Does your function need to run this code 3 times

Why? I just need (he needs) to know if a value is IN a list of values or, saying it in a "reverse way", if a list of values contains a specific (specified) value.

The difference with SQL is that you perform this check on each record of a table.

Gianni Sassanelli · Jul 30, 2018

Erel said:

Yes:

B4X:

    If IsIn("Val1", Array("Val1", "Val2", "Val3")) Then
       Log("Yes")
   End If

Sub IsIn(value As String, items As List) As Boolean
   Return items.IndexOf(value) > -1
End Sub

tank's Erel

Gianni Sassanelli · Jul 30, 2018

Mahares said:

You can do this:

B4X:

Dim RoleName As String
    Select RoleName
        Case "Val1",  "Val2" ,"Val3"
            'do something
            Log("my choice")
        Case Else
            'do something else
            Log("not my choice")
    End Select

thank's

Gianni Sassanelli · Jul 30, 2018

LucaMs said:
Maybe I can explain better what I mean so:

You also are comparing just one value, here: the current value of "make" (or, better, the value of "make" of the "current" (each) record.

thank's

Android Question IN OPERATORE LIKE SQL

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