Select data by attributes

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Claudia
Claudia 2012-5-21
Hi
I have a 24000x1 Geographic Data Structure (let's call it "Polylines" with more than 20 attribute fields. I always only like to do calculations with some of the data of this stucture. Let's say I have the field "Accuracy" and now I only like to do calculation with the data which have the string "acc" in that field. I am not sure if it is important but the structure is an element-by-element-organization. How can I select these data? Thank you for your help, Claudia

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Geoff
Geoff 2012-5-21
Do you mean you have a structure:
Polylines.Accuracy
Polylines.SomeOtherField1
Polylines.SomeOtherField2
... etc
And the Polylines.Accuracy field is exactly equal to the string 'acc' for all the rows you're interested in?
And the Polylines.Accuracy field is perhaps a cell array?
IF that were the case, you could do this:
validRows = strcmp( Polylines.Accuracy, 'acc' );
And then use that as a logical index on all fields you are interested in.
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Claudia
Claudia 2012-5-21
Hi Geoff
just watched a video about struct and arrays.
I already tried to change the organization
from 'array of struct' (synonym for 'element-by-element organization', yes?)
to 'struct of array' (synonym for 'plane organization', yes?)
It did not work. I posted the question but could not get an answer. It was not me who created the file.
Do you know how I can change it afterwards?
That would be great!
I go home now and wish you a nice day or evening, wherever you are :-)
Cheers, Claudia
Claudia
Claudia 2012-5-21
Hi Geoff
I woke up this morning and knew the answer :-)
Now I gave the "{ Polylines.ACCURACY} " command in a similar way to all attributes and then I created the struct again with "Polylines.ACCURACY = ACCURACY" and so on for all attributes.
Thank you for putting me in the right way!
Cheers, Claudia

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