I wonder why trim curve node or subdivide curve node have diamond like field inputs? How could possibly trim start /end value be a field. I.e many different values?
Or it’s supposed to accept different start/end values for different splines withing same curve?
Could somebody show an example how field could be used there?
Thanks 
KDLynch
Is it for random value only or there is a way to give a specific end value for each specific spline?
until we get a node that allows us to build custom fields, mebbe not quite how you’re thinking… but you probably could use a float curve in the meantime, like this:
Thanks again KDLynch
But I am more interested in something like giving spline5 end value 0.5 , spline8 end value 0.3 and all the other splines 0.9? Or it’s more about selection input rather than field input for the end ?
Maybe Accumulate field node could do it ?
it’s doable, just not in the way we’d like, being able to create a list of values to use as a field.
i’ve not worked with the accumulate field node yet, so that might? be a way as well. 
(having just glanced over it’s manual page, though, i suspect that’s not gonna be it)
I am not sure I understand this accumulate field node . But year we need a list of values for different spline indexes my guess. Maybe it’s one that could do it.
I guess you could do it with Selection: setup several Trims with different non-overlapping selection inputs… but it’s only practical if you don’t have many of those 
Or make a “list” with a Named Attribute:
Anurag’s example is a good one…
Another common example of a use-case is to use the factor of an instancing spline to control the lengths:
This is not useful way of thinking about fields as it doesn’t have general application (even though you can do it as demonstrated by KDLynch and StrayBillie). Anurag’s example and mine show more useful approaches where you care less about the spline’s index and more about its context in how/where it is generated.
No, this is a red herring - You use Accumulate fields for other things (like stacking boxes).
Good luck!
Thanks a lot guys and especially StrayBillie
your example does exactly what I am trying to do. Not really a function to control the ends but rather an exact list.
Wonder if we have any other ways to create such “lists” ?
Could it be done with some text file , string node maybe ?
Here is a node i made once. It is limited to 10 values. You could easily extend the node chain to support for more. But i only use those manual created fields on smaller domains, because as @zeroskilz said it is a not a good general approach. But sometimes i can not find a better solution and it became somehow “handy” (…And occasionally i love to work physically):
trim_field_by_hand_demo.blend (1.1 MB)
ooh… neat way of building a field.
One trick I do to create “lists of input values” is to create a separate object - a mesh, with just a line of vertices (don’t even need to be connected) - and then move each point’s x, y, and z positions around so as to create a list (with either 3-vector values or up to 3 float values) and use that object as an input into the geometry node tree, and sample its position by index.
