[Qgis-user] ordering an attribute table

[Nathan Woodrow]

I don't see any null or no numbers in that column.  The field is a integer
type which can't have NULL or non numbers in it to start with.

- Nathan


On Sat, Sep 28, 2013 at 12:56 AM, Michael Spencer
<spencer.mike.r at gmail.com>wrote:

> It's a 5km grid of Scotland. I've stuck it on Ubuntu One. Zip file is 54.2
> kB, located here: http://ubuntuone.com/5xQiQg5d2Gel1FYYhZDwee
>
> There's no super rush, it's for a blog how to for displaying two raster
> values at the same time.
>
> Thanks in advance,
> Michael
>
>
> On 27 September 2013 15:44, Nathan Woodrow <madmanwoo at gmail.com> wrote:
>
>> How big is your layer and could you upload it to somewhere for me, and
>> others, to test (note that I'm going to bed now so may not answer until
>> tomorrow)
>>
>> - Nathan
>>
>>
>> On Sat, Sep 28, 2013 at 12:38 AM, Michael Spencer <
>> spencer.mike.r at gmail.com> wrote:
>>
>>> Thanks Nathan,
>>>
>>> I see where you're coming from, but it's not working. The regex selects
>>> all values. I wonder if the problem lies in the data table? The column
>>> format is 'real' and I generated the column using the zonal statistics
>>> plugin from an underlying raster overlain with a regular grid. Null values
>>> seem to have been produced for cells outside the raster, with nan produced
>>> where the raster has no data.
>>>
>>> I recoded the raster output from grass to classify the no data values as
>>> -999. How do I go about selecting these? I thought "column" < 0 would work,
>>> but this doesn't select anything.
>>>
>>> Another option could be to use the raster tool and vectorise it,
>>> unfortunately this doesn't produce a whole grid as it only outputs integer
>>> values and joins some cells together.
>>>
>>>
>>> On 27 September 2013 13:44, Nathan Woodrow <madmanwoo at gmail.com> wrote:
>>>
>>>> Hey Michael,
>>>>
>>>> Try this expression using the advanced selection feature:
>>>>
>>>> regexp_match('column', '\\d*') = 1
>>>>
>>>> This is using a regex to match column as any number of digits (\\d*).
>>>>  If it's not a digit it will return 0 so you want to only select the ones
>>>> that = 1.
>>>>
>>>> - Nathan
>>>>
>>>>
>>>>
>>>> On Fri, Sep 27, 2013 at 10:16 PM, Michael Spencer <
>>>> spencer.mike.r at gmail.com> wrote:
>>>>
>>>>> Date: Thu, 26 Sep 2013 18:18:10 +0200
>>>>> From: Bernhard Str?bl <bernhard.stroebl at jena.de>
>>>>>
>>>>>
>>>>> Hi,
>>>>>
>>>>> Am 26.09.2013 18:07, schrieb Michael Spencer:
>>>>> > Having a strange problem at the moment.
>>>>> >
>>>>> > If I open a vector attribute table and click on a column heading to
>>>>> sort
>>>>> > the column then this doesn't seem to work. The column contains mainly
>>>>> > numbers with some NA and some NULL strings.
>>>>> >
>>>>> > The sort action groups most together most NA and NULL, and orders the
>>>>> > numbers, but some strings slip through the gaps and appear where they
>>>>> > aren't wanted in the number sequence!
>>>>> >
>>>>> > I'm working in QGIS 2.0.1 on Ubuntu 12.04.
>>>>> >
>>>>> > The reason I want to do this is to delete all records that aren't
>>>>> > numeric, so if there's a neater way to accomplish this that would be
>>>>> great!
>>>>>
>>>>> A neater way would be to select the records in question and then simply
>>>>> delete the selected. Hint select for nulls with
>>>>> <code>"my_field" is null</code>
>>>>>
>>>>> Thanks Bernhard, this was my original choice. Unfortunately I find the
>>>>> select tool a total black box and can't get my head around it. Your
>>>>> suggestion works for entries with 'null' in, but I can't get a response
>>>>> when I want to select 'nan' values. I've tried as:
>>>>>
>>>>> <"field" is nan>
>>>>> <"field" is 'nan'>
>>>>> <"field" = 'nan'>
>>>>>
>>>>> Both with no joy. Is there a crib sheet somewhere with basic options
>>>>> on?
>>>>>
>>>>> Ta,
>>>>> Michael
>>>>>
>>>>> Bernhard
>>>>>
>>>>> >
>>>>> > Ta,
>>>>> > Michael
>>>>>
>>>>> _______________________________________________
>>>>> Qgis-user mailing list
>>>>> Qgis-user at lists.osgeo.org
>>>>> http://lists.osgeo.org/mailman/listinfo/qgis-user
>>>>>
>>>>
>>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20130928/47550fc4/attachment.html>