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iOS

Mike Zhu
Mike Zhu
1,840 Points
Posted by Mike Zhu
Mike Zhu
1,840 Points

Asking question about three dots "..." and two dots ".." in the range of programming language

Now I am quite struggle about the range, what is the difference between the three dots like, ... and two dots like, .. in a kind of range between two integers.

Such as: UInt32(50)...UInt32(200) and UInt32(50)..UInt32(200)

Basically it is a swift project.

1 Answer

Timothy OBrien
Timothy OBrien
2,832 Points

Hey Mike,

Swift has two Range Operators - the first one is 3 period characters (...) and creates ranges that run from a to b (including both a and b in the range)

Example:

var a = 10
var b = 12
let range = a...b // includes integers 10,11 and 12

The second type of Swift range uses the ..< operator and runs from a to b but does not include b in the range

Example:

var a = 10
var b = 12
let range = a..<b // includes integers 10 and 11 only

I suggest pasting the examples into a Playground in Xcode - you should be able to then inspect the values of each range type.

Hope this helps!

Tim