The incident happened around 6:30 p.m. Friday, when the 24-year-old victim was walking into an apartment building on Neilson Street.
Authorities say he was approached by another man, who threatened him with a gun and demanded the victim's clothing. The victim handed over his pants, jacket, suit jacket and set of keys.
The suspect then fled, and there were no reported injuries.
Police later arrested 20-year-old Angel Valentin. He is charged with robbery, stalking, menacing, criminal possession of stolen property and harassment.