Pineapples are classed in a different category of fruits other than citrus.
However pineapples do belong to the family of citrus fruits but the pineapple is not classified as citrus fruits.
Pineapples are a Tropical Fruit and are citrus though.
The Pineapple belongs to the family of fruits known as the Ananas genus.
Some fruits while being citrus fruits are not considered by some as citrus fruits although they are indeed citrus fruits.
The Pineapple is basically a Tropical Citrus Fruit.
Although some other people may disagree.