Get number of nth component

I created a component which shows information for one day.
Now I duplicated this component 6 times so I got one component for every day in the week.

Every component has a global variable called "thisDay" where I set the day (day 0 = today, day 1 = tomorrow...). The components then take this global and do different calculations, specific for that day / read from an array.

That means when I want to do a change, I usually change the first component, delete the others and then duplicate it 6 times again that the change will show up in all days. I then have to change "thisDay" inside these 6 components manually. Is there a way to do that automatically, something like that I say "thisDay = nth component"?

Thanks a lot!