Yes, it's very easy to tell the difference between the sexes in snakes. Males tails are thicker just after the vent(cloaca) than a female's, and the males is also longer because it stores the dual sex organs known as "hemipenes"(two penis')on each side of the tail. In adult male snakes, they can often have a slight bulge just past the vent as well.
A female's tail tapers more abruptly past the vent, and is shorter in comparison to a male's tail.
To give you a better visual idea of what to look for, I've included a link to a well-known cornsnake breeder that has some video's on how to sex snakes. This should make it easy to understand.
A young hatchling snake can be sexed by what is known as "popping". When this method is performed correctly, if it's a male snake, you will see the two little hemipenes pop out of the cloaca vent,....on the other hand, if nothing comes out, and all you see are two "dots" on each side, these are the pheromone "scent" glands of a hatchling female.
Anyway, here is the link so you can actually see for yourself how it is done. Keep in mind, your adult snake will have to be "probed" instead of being "popped" like a hatchling would be to know what sex it is.
Here's the link........
Sexing snakes
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"Better to be silent and thought a fool, than to open mouth and remove any doubt!"