Check if 2 objects positions are close enough

How would I go about checking to see if two objects positions are pretty close to each other? The reason being is that I have a grid based movement for my player piece and when it moves onto certain pieces, I want to check to see if their position is pretty much the same so I can then do certain functionality relating to that grid piece position. I say pretty much because as the piece moves now in set distances, it is never in a whole number (say its x position is 0, then when it moves 1 unit to the left, it becomes 0.9998 or 1.0002, etc.)

What I think would be the way to do it would be:

 if(player.position.x >= grid.position.x - 0.1 || player.position.x <= grid.position.x + 0.1)
 {
 canDoStuff = true;
 }

Then repeat for the y and z co-ordinates.

This seems like a long way around and was wondering if there was a unity function (min/max range?) that would make this easier?

So it would be in pseudocode: if player.position.x == grid.position.x give or take a few.

Cheers.