topic Offset in Class() in QlikView

Offset in Class()

Anonymous — Mon, 01 Feb 2016 11:36:20 GMT

Hello Qlikers,

Can somebody help me to find out how Offset works in Class() Function??

=Class(10,5,'X',3)

How this 3 will be used in calculation while calculating expression?

Re: Offset in Class()

Chanty4u — Mon, 01 Feb 2016 11:38:57 GMT

hi,

example

class( var,10,'x',5 ) with var = 23 returns '15<=x<25

Re: Offset in Class()

jyothish8807 — Mon, 01 Feb 2016 11:39:40 GMT

Hi Balraj,

In class function 0 is normally the default starting point of the classification. By setting an offset you can change the default starting point.

Regards

Re: Offset in Class()

Anonymous — Mon, 01 Feb 2016 11:40:11 GMT

Dear,

I already know this, I am asking how offset 5 is getting calculated here?

Re: Offset in Class()

sunny_talwar — Mon, 01 Feb 2016 11:44:16 GMT

Seems to determine where you class starts from. Look at this example:

Table:

LOAD Age,

Class(Age, 5, 'X', 3) as Class1,

Class(Age, 5, 'X') as Class2;

LOAD Ceil(Rand()* 99) as Age

AutoGenerate 1000;

Output:

Re: Offset in Class()

Anonymous — Mon, 01 Feb 2016 11:47:06 GMT

Jyothish,

Thats fine. But I tried lot with Class() calculation, here are some example:

=Class(30,4,'X',9) gives 29<=X<33

=Class(30,4,'X',8) gives 28<=X<32

=Class(30,4,'X') gives 28<=X<32

How this offset values are being used here, like?

30-9+4 or 30+9-4 like this?

Re: Offset in Class()

Anonymous — Mon, 01 Feb 2016 11:49:51 GMT

Sunny, thanks for sharing this...My concern is how this offset value change the min and max value?

Re: Offset in Class()

sunny_talwar — Mon, 01 Feb 2016 11:53:23 GMT

Change the min and max value? of the underlying field?

Re: Offset in Class()

Anonymous — Mon, 01 Feb 2016 12:02:00 GMT

mean to say,

For age 1, with offset how it is giving -2<=x<3

Re: Offset in Class()

MK_QSL — Mon, 01 Feb 2016 12:09:07 GMT

From Sunny's example

Class(Age, 5, 'X') as Class2

First Class starts from 0 to 5 as no offset is given... 1st class is 0<=X<5

But for below example

Class(Age, 5, 'X', 3) as Class1

Offset is 3..and Class range is 5... Here with offset the 1st Class with end with the offset value i.e. 3

So the range would be

SOMENUMBER <= X < 3

but you have Class Range is 5 so 3-5 = -2

Range is -2<=X<3

Re: Offset in Class()

sunny_talwar — Mon, 01 Feb 2016 12:13:22 GMT

So I guess that your range either needs to start with offset value or end with it. I tried this:

Table:

LOAD Age,

Class(Age, 5, 'X') as Class,

Class(Age, 5, 'X', 1) as Class1,

Class(Age, 5, 'X', 2) as Class2,

Class(Age, 5, 'X', 3) as Class3,

Class(Age, 5, 'X', 4) as Class4;

LOAD Ceil(Rand()* 99) as Age

AutoGenerate 1000;

Output:

For 1 the range start at 1, but for 2, 3, 4, it ends at the offset value. So it would depend how your underlying field data is If there were values like -1, then I would have assumed that for range 1 also it would have started like -4<=X<1

Re: Offset in Class()

Kushal_Chawda — Mon, 01 Feb 2016 12:18:01 GMT

as You have given the offset '3' (Bucket will start from 3 if values are between 3 to 😎 else for Age 1 which is not falling in 3 so. 1-3 =-2. hence -2 to 3

Re: Offset in Class()

Anonymous — Mon, 01 Feb 2016 12:25:43 GMT

So, how QV decide where to start with offset value and where to end with offset value?

Re: Offset in Class()

MK_QSL — Mon, 01 Feb 2016 12:28:11 GMT

For

Class(Age, 5, 'X', 1) as Class1

it is indeed start with -4 <=X < 1 but because you don't have 0 age, it's now showing...!

Use,

LOAD Floor(Rand()* 99) as Age

Instead of Ceil(Rand()* 99) as Age

Re: Offset in Class()

tresB — Mon, 01 Feb 2016 12:28:35 GMT

Offset moves the limits of interval. In Class(10,5,'X'), 5 is interval lenght and the intervals becomes like: 0-5, 5-10, 10-15, 15-20... When you put addition offset like: Class(10,5,'X' ,3), the interval starts from 0+3 to 5+3 .... i.e. 3-8, 8-13, 13-18...

Hope this helps .

Re: Offset in Class()

sunny_talwar — Mon, 01 Feb 2016 12:29:10 GMT

Since the lowest observation is 1 there is no point doing -4<=X<1 as nothing will be included in it. So it starts from 1<=X<6. But for other options such as offset 3, it would include 1 within -2<=X<3 so it starts from there.

Re: Offset in Class()

MK_QSL — Mon, 01 Feb 2016 12:30:18 GMT

If no offset, the first range with Start with 0

If offset, the first range will end with that offset integer...

SIMPLE !

Re: Offset in Class()

ahbzshk07 — Mon, 01 Feb 2016 12:47:33 GMT

hello Balraj!

Consider your example as

=Class(var,5,'X',3)

we see that the offset value is 3. So among all the class interval values (depending on var), 3 has to be the either limits (lower & upper) of two of the class intervals.

Now you have interval range of 5.

With these data, you get the base class interval values i.e. a set of {-2,1,0,1,2} when upper limit is 3. => i.e. -2 <= x < 3

and {3,4,5,6,7} when lower limit is 3. => 3 <= x < 7

Now that you have got the base range, you can get other class intervals on similar line.

If var=1, o/p will be 2 <= x < 3

If var=7, o/p will be 3 <= x < 7

If var=8, o/p will be 8<= x < 13

and yes, in your example var=10. so it falls in the range of 8<= x < 13

I hope this is helpful.

Regards.