Recursive Python Function

JohnDye

So I have no clue how to do this but I'm 99% positive it's possible...I think.

I need to execute a function against every single feature in a feature class, but in a sequential and recursive manner. So let's say I'm creating a network value for each feature. The network value for each feature depends on the value of other items in the network. So every time the network value for a feature is calculated, all previously calculated values must be recalculated in order to account for the value of the newly calculated feature's network value.

So, let's say I have a feature class

FeatureClass
[TABLE="class: cms_table_cms_table_grid"]IDShapeNameNetwork Value1PointFeature1<Null>2PointFeature2

<Null>3PointFeature3

<Null>4PointFeature4

<Null>5PointFeature5

<Null>
[/TABLE]



I want to calculate the value for Feature1.
[TABLE="class: cms_table_cms_table_grid"]IDShapeNameNetwork Value1PointFeature11002PointFeature2

<Null>3PointFeature3

<Null>4PointFeature4

<Null>5PointFeature5

<Null>
[/TABLE]




Then I want to calculate the value for Feature2.
[TABLE="class: cms_table_cms_table_grid"]IDShapeNameNetwork Value1PointFeature11002PointFeature2

933PointFeature3

<Null>4PointFeature4

<Null>5PointFeature5

<Null>
[/TABLE]



But now there are multiple items in the network which means that now Feature1's network value is possibly incorrect, so Feature1 has to be recalculated..
[TABLE="class: cms_table_cms_table_grid"]IDShapeNameNetwork Value1PointFeature1982PointFeature2

933PointFeature3

<Null>4PointFeature4

<Null>5PointFeature5

<Null>
[/TABLE]



Now calculate the network value for Feature3, then recalculate Feature2, then recalculate Feature1
[TABLE="class: cms_table_cms_table_grid"]IDShapeNameNetwork Value1PointFeature1922PointFeature2

883PointFeature3

764PointFeature4

<Null>5PointFeature5

<Null>
[/TABLE]

So on and so forth until I've calculated a network value for Feature5 and recalculated the values for features 1-4

Then stop the iteration.

any help or info is appreciated...

Zeke

Well, like I said, I was kind of nitpicking. A true recursive function is one that calls itself, not one that is called multiple times in a loop. A classic example is finding factorials:

def factorial( number ):
     if number <= 1:
         return 1
     else:
         return number * factorial( number - 1 )

You could do the same thing in a loop, which is usually easier to understand, but a recursive call is much more efficient - runs faster, less overhead, etc. - in many cases.