A woman was attacked inside a Princeton University library on Monday by an unknown man while she was working in an upstairs room, school officials said. Princeton’s Department of Public Safety said Tuesday it was investigating after the woman was shoved against a wall by her neck inside the Lewis Science Library. The suspect was described as a man between 25 and 30 years old, with a brown sweatshirt, brown pants, black backpack, and dark-colored hair officials said. The assault happened on the fourth floor, officials said. Nine study rooms are spread between the third and fourth floors, accord…