Does an ipad and ipod work the same as an iphone?

I have an android and does not wish to get an iPhone but I do want an iPad or iPod. Is there a vast difference in the three

The iphone will usually have more memory on it with a minimum of 32gig or something to that effect and of course has calling and texting capabilities where the ipod and ipad do not. If you already have a phone that you like then an ipod would work well for you for music or games but really your android does everything that all of these products do.

"I do want an iPad or iPod. Is there a vast difference in the three"

That would depend on what you consider to be differences and how much you consider to be "vast".