Slices in Modelica
model Slices
import Modelica.Utilities.Strings;
import Modelica.Utilities.Arrays;
function printArray
input String[:] arr;
algorithm
Modelica.Utilities.Streams.print(Arrays.toString(arr));
end printArray;
equation
// Unlike arrays, lists in Modelica are not fixed-size.
// We'll use arrays to demonstrate similar concepts.
String[:] s;
s := fill("", 0);
Modelica.Utilities.Streams.print("uninit: ");
printArray(s);
Modelica.Utilities.Streams.print(" " + String(size(s, 1) == 0));
// To create an empty array with non-zero length, we can use the fill function
s := fill("", 3);
Modelica.Utilities.Streams.print("emp: ");
printArray(s);
Modelica.Utilities.Streams.print(" len: " + String(size(s, 1)));
// We can set and get just like with arrays
s[1] := "a";
s[2] := "b";
s[3] := "c";
Modelica.Utilities.Streams.print("set: ");
printArray(s);
Modelica.Utilities.Streams.print("get: " + s[3]);
// size returns the length of the array as expected
Modelica.Utilities.Streams.print("len: " + String(size(s, 1)));
// In Modelica, arrays are fixed-size, so we can't directly append.
// Instead, we can create a new array with the additional elements
s := cat(1, s, {"d"});
s := cat(1, s, {"e", "f"});
Modelica.Utilities.Streams.print("apd: ");
printArray(s);
// We can create a copy of an array
String[:] c;
c := s;
Modelica.Utilities.Streams.print("cpy: ");
printArray(c);
// Modelica supports array slicing with the syntax array[start:end]
String[:] l;
l := s[3:5];
Modelica.Utilities.Streams.print("sl1: ");
printArray(l);
// This slices up to (but excluding) s[5]
l := s[1:5];
Modelica.Utilities.Streams.print("sl2: ");
printArray(l);
// And this slices up from (and including) s[3]
l := s[3:end];
Modelica.Utilities.Streams.print("sl3: ");
printArray(l);
// We can declare and initialize an array in a single line
String[:] t;
t := {"g", "h", "i"};
Modelica.Utilities.Streams.print("dcl: ");
printArray(t);
// Modelica doesn't have a built-in equality function for arrays,
// so we'll need to compare them element by element
String[:] t2;
t2 := {"g", "h", "i"};
if Arrays.isEqual(t, t2) then
Modelica.Utilities.Streams.print("t == t2");
end if;
// Modelica supports multi-dimensional arrays
Integer[3, :] twoD;
for i in 1:3 loop
Integer[:] innerArray;
innerArray := fill(0, i);
for j in 1:i loop
innerArray[j] := i + j - 1;
end for;
twoD[i, :] := innerArray;
end for;
Modelica.Utilities.Streams.print("2d: ");
for i in 1:3 loop
Modelica.Utilities.Streams.print(Arrays.toString(twoD[i, :]));
end for;
end Slices;
This Modelica code demonstrates concepts similar to slices in other languages, using arrays. Modelica arrays are fixed-size, so some operations like appending are implemented differently. The code includes examples of array creation, manipulation, slicing, and multi-dimensional arrays.
Note that Modelica doesn’t have a direct equivalent to Go’s slices, so we’ve used arrays and provided similar functionality where possible. The printArray
function is a helper to print array contents, and we’ve used the Modelica.Utilities.Streams.print
function for output.
To run this Modelica code, you would typically use a Modelica simulation environment or compiler, which would handle the execution and output of results.