I have a file gdb containing the following items, and I am using version 10.8.2
200 line feature classes currently named Contour_Tile1, Contour_Tile2, etc...
I also have a single polygon feature class named Index_5000ft. It contains 200 polygons (one bounding polygon for each of the previously mentioned line feature classes). In the polygon attribute table there is a column named [Tile_Num] and it contains values like GAW_30310026. There is no correlation between the name of the line feature class, and the polygon that it might fall within. For example, all the lines in the Contour_Tile1 FC, might fall inside an index polygon with the attribute of GAW_30310026. The only thing they have in common is their spatial relationship (extent).
Lines contained within any one of the line feature classes, will always fall completely within a single polygon found in the Index_5000ft FC. Lines from a single FC will never intersect with more than one index polygon.
What I want to do is rename each of the line feature classes from Contour_Tile1, to something like GAW_30310026, which is found in the [Tile_Num] column of the corresponding polygon attribute table.
FYI: Right now I'm only having to deal with 200 tiles, but I will need to repeat this process many more times, so "automation" is the only way I can make this work. In other words, I can't resort to manual renaming because I will have many thousands of FCs to deal with. Does anyone have any ideas on how to rename the line FCs, as described here?