How to pick 1 loop edge from every 2 loop edges? means skip 1 loop edge pick up 1 loop edge , how?

I think you might have to write some code to do this. Possibly by manually walking the edges yourself and skipping every other edge.

I have checked some algorithm , it's complex for me . I don't understand programming . The algorithm seemingly base on the feature of neighbours of faces or edges. Hope give directions. Thank you.(Why sidefx not have this function？)

Walking the edges to select loops or rings would be really hard in VEX. There aren't any inspection functions for edges, and a bit array data structure to make things easier. There are neighbour functions though.

You can provide an edge group to AttribWrangle SOP but it will be converted to your Run Over type (points or primitives), so you will lose point pair information for edges. You can probably alleviate this with Python where you might be able to preserve the point pairs and use them.

I did a similar thing using Python to parse asset parameters and then use them in VEX code here. Nothing fancy:
https://www.orbolt.com/asset/animatrix::attribVarmap::1.00 [orbolt.com]

If I am not wrong, SESI doesn't recommend dynamically generating code to be used in Wrangle SOPs. But I find the productivity of writing a single code higher than custom tailoring the same code for different scenarios. Generics would solve most of these issues. I have been told SESI considered generics for VEX strongly though

There is also this asset that selects edge rings procedurally that might give you ideas:
https://www.orbolt.com/asset/animatrix::selectEdgeRing::1.00 [orbolt.com]

I would recommend doing it all in Python by using the Python SOP in H13 first for easier experimenting. You will have to implement a proper edge loop operator though, because skipping edges is a special case of an edge loop tool.

Maybe someone might have a more creative solution

thanks