topic Re: Problem with peek() in QlikView

Problem with peek()

nicolas_martin — Thu, 08 Oct 2015 14:07:01 GMT

Hello,

I would like to loop on every value of a field, with the "peek" function.

The following code works:

Table1:
LOAD * INLINE [
Field1
Aaa
Bbb
Ccc
];

LET nbVal = FieldValueCount('Field1');

FOR _i = 0 TO nbVal - 1
  LET _val = peek('Field1', _i);
  LET _res = MsgBox('$(_val)');
NEXT _i

This will pop up "Aaa", "Bbb" and "Ccc".

But if I load another table between the table and the loop, it doesn't work anymore:

Table1:
LOAD * INLINE [
Field1
Aaa
Bbb
Ccc
];

LET nbVal = FieldValueCount('Field1');

Table2:
LOAD * INLINE [
Field2
1
2
3
];

FOR _i = 0 TO nbVal - 1
  LET _val = peek('Field1', _i);
  LET _res = MsgBox('$(_val)');
NEXT _i

I don't understand why loading another table prevents the "peek()" to succeed.

If I'm adding the table:

LET _val = peek('Field1', _i, 'Table1');

it works.

Does that means the function "peek" with 2 parameters is not reliable?

Re: Problem with peek()

Anonymous — Thu, 08 Oct 2015 14:08:52 GMT

Hi,

Table1:

LOAD * INLINE [

Field1

Aaa

Bbb

Ccc

];

LET nbVal = FieldValueCount('Field1');

Table2:

LOAD * INLINE [

Field2

];

FOR _i = 0 TO nbVal - 1

LET _val = peek('Field1', _i,'TableName'); //Give table name here when another table in between

LET _res = MsgBox('$(_val)');

NEXT _i

Re: Problem with peek()

nicolas_martin — Thu, 08 Oct 2015 14:12:04 GMT

Indeed, but I would like to understand why.

The "Field1" field is only in the table "Table1". Why do I have to make the precision?

Re: Problem with peek()

Anonymous — Thu, 08 Oct 2015 14:16:23 GMT

Hi,

The Peek() function can be used in a load to retrieve data from the same table or from another table. in these case the table name is mandatory, as table which we are refering is not immediate table in the script.

Re: Problem with peek()

nagaiank — Thu, 08 Oct 2015 14:22:27 GMT

The Reference manual states that if the Tablename argument is not specified, the current table is assumed. If you want to refer any table other than the current table, you need to specify the table.

Re: Problem with peek()

nicolas_martin — Thu, 08 Oct 2015 14:42:25 GMT

Thank you.

I misunderstood the meaning of the phrase in the Reference Manual.

I thought it was "it takes the last table having this field".

Re: Problem with peek()

Anonymous — Thu, 08 Oct 2015 14:43:47 GMT

Hi Nicolas,