modelx fails to correctly restore the data types (dtypes) of string columns that only contain numeric values

[fumitoh]

Hi, I am really excited to test various modelx features nowadays.

I want to ask some tips about preserving the data type of ref data ( which I get via new_pandas function) after saving the model.

Below is an example which I faced some trouble.

1) I make ref variable in my model by using the code below

df = pd.read_csv('test.csv', dtype = {'PROD_CODE' : 'string', 'PLAN_CODE' : 'string'}, index_col=['PROD_CODE', 'PLAN_CODE'])
P.new_pandas("test","test.csv",data=df,file_type ="csv",sheet = "sheet1")

sample data

PROD_CODE PLAN_CODE RATE
"1111","0055",0.04
"1112","0001",0.03

2) I can get exact same data when I make the ref varable "test"

3) However, after I saved the model, it seems the data type I assigned to each column ( STRING to "PROD_CODE" and "PLAN_CODE" disappear)

--> When I reload the model, the data changed as below

after reloading the model

PROD_CODE PLAN_CODE RATE
1111,55,0.04
1112,1,0.03

If there is any way to preserve the data type of each column I first assigned, pleas let me know.

Thank you for reading my question!

Originally posted by @LimYoonhwan in https://github.com/fumitoh/modelx/discussions/107