QlikView equivalent of Python's List to store field's names as a variable and then used to load a dataset

[fishing_weights]

Hi all

I have a list of field names that I would like to store in a variable/ list and then used to load datasets from the server.

example 

vlistofFieldNames = ('F1','F2','F3','F4','F5')

then to load my datasets. Example:

[Table1]:

SELECT vlistofFieldNames

FROM database_1

WHERE date = '2023-01-01';

[Table2]:

SELECT vlistofFieldNames

FROM database_2

WHERE date = '2023-01-01';

Is that possible and what would the syntax be like? Thanks in advance

[marcus_sommer · Accepted solution]

It's possible and there are probably multiple ways to specify the creating and calling of the variable. Personally I use mostly;

set vlistofFieldNames = "text([F1]) as [Fx],[F2] as [Fy],[F3],[F4],[F5]";

[Table1]: load $(vlistofFieldNames) from ...

which means not only fieldnames else entire (load) statements could be specified. By loading from a data-base you need of course using their wrapping- and functions-syntax/portfolio.

[fishing_weights]

@marcus_sommer  Thank you very much !

A follow up question, is there a way to remove a field/value in code from the variable?

Example I declared:

set vlistofFieldNames = "text([F1]) as [Fx],[F2] as [Fy],[F3],[F4],[F5]";

but since one or two datasets out of 100 does not have the field: F5, 

can I do the python equivalent of : vlistofFieldNames. drop("F5")

resulting in my variable becoming vlistofFieldNames = "text([F1]) as [Fx],[F2] as [Fy],[F3],[F4]";

[marcus_sommer · Accepted solution]

Not in this sense because the variable here is a string and not an array or a list. This means it would need something like:

let var = replace('$(var)', '[F5]', '');

but depending on the position of the entry you may need to remove also a comma respectively by multiple entries and/or more complex logic some extra checks and handling.

An alternatively may be to load the field-list in a table, like:

t1: load * inline [
F
F1
F2 as F3
...
];

and then something:

t2: load concat(F, ',') as X resident t1;

let var = peek('X', 0, 't2');

The tables could be now regarded as array and not wanted fields/statements could be removed with a where-clause.