Original post

primes := [6]int{2, 3, 5, 7, 11, 13}
fmt.Println(primes[1:4])

results:
[3 5 7]
My expertise is Ada language, why isn’t the printing results [3 5 7 11]?
Why is the last element of the array slice not output in print?

Slices in are source[starting_index : ending_index+1] conceptually:

var target []int

for i := starting_index; i < ending_index; i++ {
    target = append(target, source[i])
}

https://play.golang.org/p/8qrobCLylnA

Sean, Thank you Sir! That makes the engine under the hood perfectly clear to me.

No problem! While we’re mentioning “the engine,” I just want to be explicit: My conceptual example actually creates a copy but slicing doesn’t really create a copy, it adjusts the underlying array pointer, length and capacity.

Thanks. I’m trying to wrap my head around that. The Slices have the smell of pointers to a portion of the original variable. Am I correct in that assumption?

Absolutely. Here’s a demo: https://play.golang.org/p/kRnCP8PLsJD

Thank You Sean,
I know it’s late into July but I’m just now getting some time to actually sit behind a keyboard, other than at work. Slices appear to be very Python like. I’m not a Python user, just forced into using it at work every so often. But sincerely thankful for your thorough reply. I had seen your reply in May and I apparently rudely neglected to say thanks.
Mike

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