Counting entries in a list

[Johnny Karms Pedersen]

Hi,

I'm working on a service that provisions prefix lists for customer services. The prefix-lists are of variable sizes and due to that, I want to know the number of entries in my (yang-) list when running my template.

In my template, the last entry will be treated differently than the previous and I need a hint how to do this. (In IOS-XR the every prefix-set entry is ended with a comma, except for the last one).

TIA.

/Johnny

[vleijon]

In XPath you have access to a number of built-in functions, in particular you have access to count(), which counts the number of nodes in a list and position() which gives the current index. Hopefully you can use a combination of those to achieve the result you want.

I would like to take this opportunity to mention that you can troubleshoot this kind of thing by doing commit | debug xpath, which gives insight into what is happening.

[hniska]

Without testing it I would assume that the NED handles the comma part automatically? Sounds like something that the NED should be handling.. 

[Johnny Karms Pedersen]

I’m using the example NED in the free trial edition, which seem to be quite limited.

It throws a fault if the comma isn’t present.

Also, it doesn’t do very well if I do updates to the prefix-set. NSO attempts to negate outdated entries, while XR requires a complete re-configuration of the prefix-set. I had hoped that “tags=‘replace’” would’ve solved this, but no luck 😐

[Johnny Karms Pedersen]

Thanks, the count() function gave me the value I needed.

I did not try the position() function, but used a traditional counter variable in the loop.