topic read and change fieldnames based on expression during load in QlikView

read and change fieldnames based on expression during load

Fri, 03 Feb 2012 15:34:26 GMT

i was searching in the reference guide for some expression that reads the fieldname like other expressions read the content of the field.

f.e. thre are filds like building1, building2, building3

the goal is, to change the format from

building1, value

23, temp

80, moist

building, b_number, value

23, 1, temp

80, 1, moist

is it possible to read these like

right(anyfildname,1) to get the numbers (1,2,3 ec.) ?

if so, it could be possible to used in an expression like this:

LET b_number = right_fieldnames(1);

LET b_number = IF (left_fieldname(5)='build', right_fieldnames(1));

is something like this possible ?

read and change fieldnames based on expression during load

erichshiino — Fri, 03 Feb 2012 16:48:06 GMT

Hi, Alexander

You can achieve this using cross table.

I wrote a sample script as an example. In this piece of code, I wrote a table using inline and store, but you can start from the second step, using crosstable on your original tables:

//Creation of Test Table

Test:

LOAD * INLINE [

STUDY, TYPE, BUIDING1, BUILDING2, BUILDING3

1, A, 200, 300, 400

1, B, 100, 50, 20

1, C, 15, 90, 400

2, A, 15, 32, 200

2, B, 200, 100, 150

2, C, 50, 100, 70

];

Store Test into Test.qvd;

drop table Test;

//QVDs will be read to simulate a source file

//Cross table could be done in the original Load Inline

tempBuildings:

CrossTable(tempBuilding, Value, 2)

LOAD STUDY,

TYPE,

BUIDING1,

BUILDING2,

BUILDING3

FROM

[Test.qvd]

(qvd);

//At this point tempBuildings has the Fields: STUDY, TYPE, tempBuilding and Value

Building:

Load STUDY,

TYPE, Right(tempBuilding,1) as Building,

Value

resident tempBuildings;

drop table tempBuildings;

Hope this helps,

Erich

Re: read and change fieldnames based on expression during load

hic — Fri, 03 Feb 2012 16:48:20 GMT

Yes it is possible. See attachment. You should look in the help at the Crosstable statement and the string functions.

read and change fieldnames based on expression during load

Fri, 10 Feb 2012 11:42:31 GMT

Im sorry, this was a missunderstanding.

the example i provided was a bit misleading.

im not looking for a crosstable statement or a string function. this wouldnt be the problem (there are tons of examples for this here)

im looking for something like

"Right(tempBuilding,1) as Building,"

but the source should be the field name (tempBuilding) and not the content.

something that just reads the number from the name of the field

LET Numfield= Right(field7,1)

Right(test_table,1) , so its gets the last digit (or char) of every fieldname in "test_table"

im sorry for the missunderstanding.

Re: read and change fieldnames based on expression during load

hic — Fri, 10 Feb 2012 11:58:17 GMT

Not quite sure I understand... when you write your Load statement, then you know the field names, so you might as well hard-code the number in the script. Or what am I missing?

Anyway, if you loop over the fields, then you can use the FieldNumber() and FieldName() functions, and in your case it could then be

Right (FieldName(2, 'Table'),1) as Building