<div dir="ltr">QgsExpression, the base for expression labels, is just not used for labels. It is also used for rules, actions, WFS filtering, attribute table filter.<div><br></div><div><font color="#000000" face="arial, sans-serif">I will consider it for string concatenation.</font></div>
<div><font color="#000000" face="arial, sans-serif"><br></font></div><div><font color="#000000" face="arial, sans-serif">- Nathan</font></div><div><div><br></div></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">
On Fri, Aug 2, 2013 at 8:28 AM, Bernd Vogelgesang <span dir="ltr"><<a href="mailto:bernd.vogelgesang@gmx.de" target="_blank">bernd.vogelgesang@gmx.de</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
mhm,<br>
<br>
Nathan, you wrote in the ticket:<br>
"String + NULL = NULL. We don't treat NULL as empty string because it's not correct to do so. NULL and empty mean two different things so are treated differently."<br>
<br>
Sorry, but for "what" is that not correct? This might apply to database actions etc. but forcing user to make somersaults with "coalesce" (what the f... is that???) to prevent empty labels ... hey! It's just labeling!<br>
<br>
Making labeling a nerd-discipline is not fair ;)<br>
<br>
Just my 2 cents<br>
Bernd<br>
<br>
Am 02.08.2013, 00:02 Uhr, schrieb Nathan Woodrow <<a href="mailto:madmanwoo@gmail.com" target="_blank">madmanwoo@gmail.com</a>>:<div class="HOEnZb"><div class="h5"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hey,<br>
<br>
QgsExpression doesn't treat NULL and Empty string as the same thing. Which<br>
is why we don't auto convert. To convert nulls in a field you should use<br>
the coalesce("Areatype",'')<br>
<br>
See <a href="http://hub.qgis.org/issues/8369" target="_blank">http://hub.qgis.org/issues/<u></u>8369</a><br>
<br>
- Nathan<br>
<br>
<br>
On Fri, Aug 2, 2013 at 7:35 AM, Larry Shaffer <<a href="mailto:larrys@dakotacarto.com" target="_blank">larrys@dakotacarto.com</a>>wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Lene,<br>
<br>
On Thu, Aug 1, 2013 at 2:25 PM, Lene Fischer <<a href="mailto:lfi@life.ku.dk" target="_blank">lfi@life.ku.dk</a>> wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Goyo<br>
The geometries is OK.<br>
I have a combined label Ex.<br>
Areatype || '\n' || $Area || ' m2'<br>
Now I found that if one field is empty (Even if there is NULL in the<br>
field), then the entire label will not be displayed.<br>
<br>
</blockquote>
<br>
When the expression-based label text was introduced, NULL values<br>
supposedly where just converted to empty strings [0], i.e. if Areatype was<br>
NULL, one would expect at least 'm2' to be present in the label.<br>
<br>
Try enclosing your field name Areatype in double quotes. Also, try without<br>
the $Area function, but still with the || concatenation. If the label still<br>
does not contain any text, then it is probably a bug in how QgsExpression<br>
handles NULL values from the data provider. If so, please create an issue<br>
ticket [1]. Include a test project file, and try to list reproducible<br>
steps, if you can.<br>
<br>
[0]<br>
<a href="http://osgeo-org.1560.x6.nabble.com/Expression-based-labeling-tp4100735p4100736.html" target="_blank">http://osgeo-org.1560.x6.<u></u>nabble.com/Expression-based-<u></u>labeling-tp4100735p4100736.<u></u>html</a><br>
[1] <a href="http://hub.qgis.org/projects/quantum-gis/issues" target="_blank">http://hub.qgis.org/projects/<u></u>quantum-gis/issues</a><br>
<br>
Regards,<br>
<br>
Larry<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Regards<br>
Lene<br>
<br>
<br>
<br>
______________________________<u></u>__________<br>
Fra: Goyo [<a href="mailto:goyodiaz@gmail.com" target="_blank">goyodiaz@gmail.com</a>]<br>
Sendt: 1. august 2013 20:40<br>
Til: Lene Fischer<br>
Cc: <a href="mailto:qgis-user@lists.osgeo.org" target="_blank">qgis-user@lists.osgeo.org</a><br>
Emne: Re: [Qgis-user] Label missing in Weekly<br>
<br>
2013/8/1 Lene Fischer <<a href="mailto:lfi@life.ku.dk" target="_blank">lfi@life.ku.dk</a>>:<br>
> Hello<br>
> I´m using the new labelfunction - it is great!! - but som of the labels<br>
are<br>
> missing. I have a small project with only 9 polygons, but only 7 labels<br>
is<br>
> visible.<br>
> I´ve tried:<br>
><br>
> Settings to "View all labels in all layers"<br>
> change attributefield and size<br>
><br>
> Same result. Any suggestions?<br>
> Regards<br>
> Lene Fischer<br>
<br>
You might have invalid geometries. They are not labelled IIRC.<br>
<br>
Goyo<br>
<br>
<br>
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</blockquote>
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</blockquote></blockquote>
<br>
<br></div></div><span class="HOEnZb"><font color="#888888">
-- <br>
Bernd Vogelgesang * Siedlerstrasse 2 * 91083 Baiersdorf * +49-9133-825374</font></span><div class="HOEnZb"><div class="h5"><br>
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