Rudy has a bit of style currency, thanks to the fact that Jude Law used it for his son. It has been consistently in the Top 1000 for as long as Social Security records have been tallied, as opposed to parent name Rudolph, which, perhaps due to the reindeer, hasn't been heard from in two decades.
Rudy has a lot going for it as a usable-on-its-own nickname name, with the lively 'oo' sound found in Jude and Juno and all the popular Lu-starting names. And it was a heartthrob name back in the day when crooner Rudy (born Hubert) Vallee and Rudy/Rudolph (born Rodolpho) Valentino had ladies swooning, reaching as high as Number 299 in 1926.
It has most often been seen as an all-male name--except for little Rudy on The Cosby Show.