Function Names
select, pickDescription
This function selects a following parameter depending on the value of the first parameter.
Positive numbers count from left to right, where 0 refers to the 2nd function parameter. Negative numbers count from right to left, where -1 refers to the last parameter.
select will calculate the expressions in all parameters.
pick will calculate the expression of the applicle parameter and skip calculating the other ones. This approach saves processing time,
especially if the expressions contain heavy calculations or large contents (e.g. sets retrieved from tables).
Call as: procedure or function
Restrictions
Indirect parameter passing is disabled
Parameter count
Min. 2
Parameters
| No. | Type | Description |
|---|---|---|
| 1 input |
numeral | Number als selector 0, 1, 2, etc. select 2nd, 3rd, 4th, etc. function parameter. -1, -2, etc. selects the last function parameter. |
| 2, etc. input |
all types | Selected value Applicable to select: The values of all function parameters will be calculated. The selected value will be returned. |
| Alt. 2, etc. code |
expression :string |
Selected expression Applicable to pick: Only the expression of the selected parameter will be calculated. The other expressions will be skipped. |
Return value
| Type | Description |
|---|---|
| all types | Selected value |
Exceptions
Value is out of bounds
Examples
a[] = 1; b[] = 2; c[] = 3; d[] = 4;
echo("Function 'select':");
for (i[] = 0, i[] <= 3, i[]++ )
{
print( select( i[], a[]++, b[]++, c[]++, d[]++ ), " " );
}
// Note: All 4 variables have been incremented 4 times.
echo(new line, " a[]..d[] = ", a[], " ", b[], " ", c[], " ", d[], " " );
echo;
a[] = 1; b[] = 2; c[] = 3; d[] = 4;
echo("Function 'pick':");
for (i[] = 0, i[] <= 3, i[]++ )
{
print( pick( i[], a[]++, b[]++, c[]++, d[]++, e[]++ ), " " );
// Note: e[] added, but will never be executed, so no error message occurs (variable not existing)
}
// Note: All 4 variables have been once only
echo(new line, " a[]..d[] = ", a[], " ", b[], " ", c[], " ", d[], " " );Output
Function 'select':
1 3 5 7
a[]..d[] = 5 6 7 8
Function 'pick':
1 2 3 4
a[]..d[] = 2 3 4 5