What it means ...arr

Question

I see code
Arr2 = [...arr]
In one of challenges (propably ruby)
What does it means (with comas)?

Answer 1

There is nothing about this comass ... before "arr" text

Answer 2

In JS ... stands for rest parameters.

Answer 3

I don't have the ruby course on here so I don't have the link for that but the php should explain it as well
https://www.sololearn.com/learn/PHP/1807/

Answer 4

It's a range object in ruby which contains numbers from n to m (n..m) or n till m (n...m)
2-dots mean inclusive of m, 3 means exclude m.

arr = [1, 20...30, 9]
puts (10..20).size #20
puts arr.length #11
puts (1..6).to_a

You can check this stackoverflow post for additional info

https://stackoverflow.com/questions/9690801/difference-between-double-dot-and-triple-dot-in-range-generation

Answer 5

That's nothing else than a symbolic for a array filled with variables