Maps of int|real array

General Discussion
1

Hello,

Do you think possible to extend the language to allow the declaration of maps of array like int[][string] or real[][string] ?

Best regards.

2

yes, but i don’t like is syntax.

and I am not sure to understand what you want,
can you explain in C++ what is the key type of the map and the mapped value type.

remark: make a double as a key value is not a good idea due to roundoff error.

to day your can do

    real[string] mapr;
    int[string] mapi;

    mapr[2.15]= 6.6;
    mapi[2]= 7;
    // here   2.15 is cast in string "2.15" and 2 in string "2" automatically
3

we misunderstood each other, the key value is always either a string or a int. The idea is have these two objects :

map<string, int>
map<string, real>
map<string, string>
map<int, int>
map<int, real>
map<int, string>

Best regards.

4

Yes for

 map<string, int[]>
 map<string, real[]>
 map<string, string[]>

this syntaxe is clear

int[string][int] 
real[string][int] 
string[string][int]

but for this other we can not used
int[int][int]
real[int][int]
string[int][int]

because it is array of array not map .

5

I better understand. Do you know when map<string,T> will be available ?
Let’s suppose ID (from a medit or gmsh mesh file) be either an int or a string, the motivation comes from the need to store solid IDs according to materials IDs (that goes the same for surface IDs according to boundary condition IDs), ids are not necesserary 0-index and must be arbitrary “big”, it’d be a pity to not use a sparse structure for IDs such as maps.
So that i could write :

int[string][int] MaterialID;
MaterialID[“45757”] = [1214,2354,396,14];
MaterialID[“14664”] = [567,47787,12];

and

cout<<"Size = "<<MaterialID.n<<endl;
cout<<MaterialID<<endl;

Size = 2
2
1214 2354 396 14 4
567 47787 12 3

cout<<MaterialID[“14664”][2]<<endl;
cout<<MaterialID[“14664”].n<<endl;

12
3

Best regards.

6

no today, It depend strongly of your need!

Best Regards,

Frédéric Hecht.