Parentheses: ()
Syntax
( op )
Input parameters
op |
the operand to be evaluated before performing other operations written outside the parentheses.
According to the general VTL rule, operators can be nested, therefore any Data Set,
Component or scalar op can be obtained through an expression as complex as needed
(for example op can be written as the expression 2 + 3 ).
|
Examples of valid syntaxes
( DS_1 + DS_2 )
( CMP_1 - CMP_2 )
( 2 + DS_1 )
( DS_2 - 3 * DS_3 )
Semantics for scalar operations
Parentheses override the default evaluation order of the operators that are described in the section “VTL-ML - Evaluation order of the Operators”.
The operations enclosed in the parentheses are evaluated first.
For example (2+3)*4 returns 20, instead 2+3*4 returns 14 because the multiplication has higher precedence than the addition.
Input parameters type
op
dataset
| component
| scalar
Result type
result
dataset
| component
| scalar
Additional Constraints
None.
Behaviour
As mentioned, the op of the parentheses can be obtained through an expression as complex as needed (for example op can be written as DS_1 - DS_2).
The part of the expression inside the parentheses is evaluated before the part outside of the parentheses.
If more parentheses are nested, the inner parentheses are evaluated first, for example ( 20 - 10 / (2 + 3) ) * 3 would give 54.
Examples
Given the operand datasets DS_1 and DS_2:
Input DS_1 (see structure)
Id_1 |
Id_2 |
Me_1 |
Me_2 |
|---|---|---|---|
10 |
A |
5 |
5.0 |
10 |
B |
2 |
10.5 |
11 |
A |
3 |
12.2 |
11 |
B |
4 |
20.3 |
Input DS_2 (see structure)
Id_1 |
Id_2 |
Me_1 |
Me_2 |
|---|---|---|---|
10 |
A |
10 |
3.0 |
10 |
C |
11 |
6.2 |
11 |
B |
6 |
7.0 |
Example 1
DS_r := (DS_1 + DS_2) * DS_2;
results in (see structure):
Id_1 |
Id_2 |
Me_1 |
Me_2 |
|---|---|---|---|
10 |
A |
150 |
24.0 |
11 |
B |
60 |
191.1 |