topic Re: FOR ... NEXT + DO while LOOP in QlikView

FOR ... NEXT + DO while LOOP

Mon, 24 Nov 2014 16:52:19 GMT

Hi All,

I'm loading web data from several links. It happens that a request returns no data (supposedly web server issues) but if requested again it does return the data. I need to implement DO while LOOP into the below code so that when the requests returns no data the loop requests again until it gets the data. I've tried with FieldValue but ended up with errors. Any help will be much appreciated.

Links:

LOAD * Inline [

http://www.rates1.com

http://www.rates2.com

http://www.rates3.com

];

Rates:

LET vNoOfLinks = NoOfRows('Links');

FOR i=0 to $(vNoOfLinks)-1;

LET vLink = Peek('Link',$(i),'Links');

LOAD

[@1:n] as Data

FROM $(vLink) (fix, utf8);

NEXT

Regards,

Przemek

Re: FOR ... NEXT + DO while LOOP

MarcoWedel — Mon, 24 Nov 2014 20:15:45 GMT

Hi,

one solution could be:

Links:
LOAD * Inline [
Link
http://www.rates.com
http://www.rates1.com
http://www.rates2.com
];

LET vNoOfLinks = NoOfRows('Links');
FOR i=0 to $(vNoOfLinks)-1;
LET vLink = Peek('Link',$(i),'Links');
Rates:
LOAD
  [@1:n] as Data
FROM $(vLink) (fix, utf8);
NEXT;

hope this helps

regards

Marco

Re: FOR ... NEXT + DO while LOOP

Mon, 24 Nov 2014 20:34:18 GMT

Hi Marco,

the file you've attached is just a reloaded code of mine? Am I missing something?

Regards,

Przemek

Re: FOR ... NEXT + DO while LOOP

MarcoWedel — Mon, 24 Nov 2014 21:34:57 GMT

Hi Przemek,

I thought you needed a version of your code that does not throw errors or am I missing something?

regards

Marco

Re: FOR ... NEXT + DO while LOOP

Mon, 24 Nov 2014 22:04:17 GMT

Ok. Let me put this way - I run the above code, the for...next loop requests data from 3 web links. Now, link 2 returns no data because of some web server error so I end up with data from link 1 and link 3. I know that at link 2 there is some data stored and if I run the code above I will most probably get the data from link 2. So, to avoid reloading whole script I want to put in do while loop to loop until every single link returns data.

In my script there's over 50 links so the do while loop must be nested into for ... next loop not the other way round.

Regards,

Przemek

Re: Re: FOR ... NEXT + DO while LOOP

MarcoWedel — Mon, 24 Nov 2014 22:41:03 GMT

Hi,

maybe like this?:

Links:
LOAD * Inline [
Link
http://www.rates1.com
http://www.rates2.com
];

LET vNoOfLinks = NoOfRows('Links');
FOR i=0 to $(vNoOfLinks)-1;
LET vLink = Peek('Link',$(i),'Links');
LET vNoOfRowsRates = Alt(NoOfRows('Rates'),0);
DO
  Rates:
  LOAD
  [@1:n] as Data
  FROM $(vLink) (fix, utf8);
LOOP until NoOfRows('Rates') > $(vNoOfRowsRates);
NEXT;

hope this helps

regards

Marco

Re: FOR ... NEXT + DO while LOOP

Tue, 25 Nov 2014 09:34:05 GMT

Beautiful! Thank you.

Re: FOR ... NEXT + DO while LOOP

MarcoWedel — Tue, 25 Nov 2014 10:51:55 GMT

You're welcome

Regards

Marco

Re: FOR ... NEXT + DO while LOOP

Sun, 30 Nov 2014 23:35:53 GMT

Hi Marco,

I'm struggling with another loop - a tuned version of the last one.

Table 'Rates' consists of sets of data from Links. Each Link set (except the last one) should have exactly 10 records including '*increase*' string. However, due to web server issue, a load from a Link happens to return less than 10 records with the string. In such cases I need to load the data again from this very Link. The last Link set may return less than 10 records and that's ok.

Any idea how to play this scenario?

Regards,

Przemek

Re: FOR ... NEXT + DO while LOOP

Anonymous — Mon, 01 Dec 2014 01:03:34 GMT

Why You do this inside Qlik View ?

Regards

Re: FOR ... NEXT + DO while LOOP

Mon, 01 Dec 2014 09:06:39 GMT

Well, there are many reasons but the bottom line is that it's comfortable to get and process the data in QV. What would suggest otherwise?

Re: FOR ... NEXT + DO while LOOP

Anonymous — Tue, 02 Dec 2014 23:36:19 GMT

On Qlik You should use the Edit only for some configuration definition and load /join of data structures.

The read/load of URL files inside qlik is not recommended for many reasons - performance is the main reason.

Generate a file, csv, a table, a qvx or better a qvd outside qlik is the best solution.

Re: FOR ... NEXT + DO while LOOP

Anonymous — Sat, 13 Dec 2014 17:52:28 GMT

Process it before call Qlik.

Any Progamming language do the job easly.

Qlik is BI tool not a PL.