Help me to understand column expression

[Goku (IamBatman)]

So i have been researching about dt.column(“col1”).expresssion but i didnt understand it
I tried to search for articles/xaml files etc but i didnt get any

So can anyone understand me what does it do

also i have a problem

Say i have a column like below example
col1
1
2
3
4
5

i want to modify that column by multipying those values with 10
How can i modify it using expressions method

Output should be
col1
10
20
30
40
50

@Anil_G or anyone else please make me understand along with examples

[supermanPunch (Arpan)]

Hi @Goku ,

Check out the below blogs/Documents :

How to Update Data Column Values of a Data Table | Community Blog

DataColumn.Expression Property (System.Data)

Recent use case or Examples :

Update a column in a datatable using LINQ

Hi @yash.choursia , An Alternate with Data Column Expression (As it is an easier/simpler operation) : Implementation : [image] Here, Notice the use of Add Data Column to add another column for updating the newer values. We then use the Data Column Expression using Assign in the below Way : DT.Columns("Updated Column").Expression = "IIF(CONVERT([Difference],'System.Double')>-1 And CONVERT([Difference],'System.Double')<1,0,CONVERT([Difference],'System.Double'))" We can also simply remove t…

[Goku (IamBatman)]

Hey @supermanPunch ,

I get this following error

Is it because we cant update the column which we have used in left side of assign activity?

Also many thanks for providing me links

[supermanPunch (Arpan)]

@Goku ,

Its Great you are already experimenting it out , So now the error shows that a circular reference is not possible.

It means, a Circular reference to update the same column cannot be referenced in your Data Column Expression.

If you have noticed the other post that I have pointed, I had created a new Column, and I have done the Calculation in that new column.

You could do the same.

[Goku (IamBatman)]

Hey @supermanPunch ,
I did as you said, i added a data column
and i got this error

I Tried using Cint([Column1]*10) but it threw me a error
Assign: The expression contains undefined function call Cint().
Can you please help me with this

I also tried something like this

but that too threw me an error

Column type Details:
Column1 - Type is string
col1 - TypeArgument is String

[supermanPunch (Arpan)]

@Goku ,

You are very close.

Analyse and check further, CONVERT() function converts to the required type, For arithmetic operations we would need it to be either Integer or Double, we could specify the required type just like you have specified ‘System.String’. Also the Multiplication(*10) applies after the conversion.

Do also closely observe the syntax, there are Open and Closing brackets mismatch.

Do let us know if you were able to correct this last segment.

[Praveen_Mudhiraj]

Hi

You can try like this it may help you

1Take for each row in data table and pass the
data table
2. Inside loop you can use like this
= cint(currentrow(0))*10

For the reference im attaching the screenshots with output please check

[Goku (IamBatman)]

Hey @supermanPunch ,
Thank you so much for previous response , now I want to concatenate that column value with a variable
I tried doing it but i got error

[supermanPunch (Arpan)]

@Goku

Say i have a column like below example
col1
1
2
3
4
5

i want to modify that column by multipying those values with 10
How can i modify it using expressions method

Output should be
col1
10
20
30
40
50

@Anil_G or anyone else please make me understand along with examples

@Goku ,

Is the Original Topic answered ? We would like to Scope the Topic for One Question/Topic, so that it is properly visualised for other users the Question/Query and the Solution, so that we also maintain the Thread Length.

Newer Topics could be created for separate queries, we can provide separate answers for it.

Regarding your last query, do analyse further (always), as you are using a variable, you should not add it within the Column Expression but after the Column Expression ends. But also enclose it within Single Quotes. As you can notice, when just the name of the Variable is added to the expression, it is just a String value and not the variable value.

You can create separate topic on this query so a better/more individual help could be provided to that.