set absolute values for Expression

Farhan Shariff

I need to set absolute value for the following expression

formula Dealt_sigma = |Mean_new - Mean_refrence| /(sigma)
delta_sigma cannot be negative.

Delta_sigma.Expression = "(Convert(mean_new,'System.Double')-Convert(Mean_refrence,'System.Double'))/(sigma)";

5 Replies

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Vulpes12y ago
Accepted answer
IIF(condition, a, b) is equivalent to the C# ternary operator:

condition ? a : b

where 'condition' is a bool and 'a' and 'b' are values of the same type.

So, if condition is true, it returns 'a' and, if it's false, it returns 'b'.

Conceptually, it's simple enough though where you have complex expressions, you can drown in a sea of brackets if you're not careful!

Check this link for everything that's allowed in the Expression property:

http://msdn.microsoft.com/en-us/library/system.data.datacolumn.expression(v=vs.110).aspx
Farhan Shariff12y ago
Seriously you are the best.It is working. I have to learn this IIF.
thanks_a_lot Vulpes
Vulpes12y ago
Good, that makes life a little easier :)

So try this:

Delta_sigma.Expression = "IIF((Convert(Mean_new,'System.Double') - Convert(Mean_refrence,'System.Double')) >= 0.0, Convert(Mean_new,'System.Double') - Convert(Mean_refrence,'System.Double'), Convert(Mean_refrence,'System.Double') - Convert(Mean_new,'System.Double'))/sigma";
Farhan Shariff12y ago
sigma is not negative or zero it is a positive value
Vulpes12y ago
You'll need to use IIF here as Math.Abs isn't supported in the Expression property.

To enable me to come up with an answer, can you advise whether the 'sigma' column could be negative or zero?