I'm assuming this is a prebuilt computer from ironside? Which for what you're getting here, ironside will charge you around $1700.
Just to show you why you shouldn't buy a prebuilt computer: https://pcpartpicker.com/list/GqNTjc
Building it yourself will save your (or your parents, if this is for you birthday) about $400.
That's not even what I would get if I were you, though. Personally, I would probably buy half of this stuff used, or if it had to be new, I would reallocate some money from the cpu to the gpu, since you won't be losing out much going with an i5 7600 instead of an i7 7700, but you will be gaining a lot of performance upgrading the gtx 1050ti to a 1060 or 1070.
If you do want an i7 though still, something like this: https://pcpartpicker.com/list/JFYtNN
is better. it's using skylake instead of kaby lake, but kaby lake has shown thus far to be pretty lackluster. You could still get a kaby lake cpu if you wanted to, because as far as I'm aware, most motherboard manufacturers have BIOS updates that support kaby laky with a z170 chipset.
You can swap out a lot of that if you want to cut costs in some places, or upgrade some parts. Like the keyboard, mouse, case, operating system, psu, etc. It's just a quick build to give you an idea.
And just a side note; this is extremely overkill for league. You can play league on almost any computer. there are videos of people playing at 60fps on computers they picked up for $25.
