Golang的“上限”

Question

This question already has an answer here:

• Is working past the end of a slice idiomatic? 2 answers

The following go code:

var numbers4 = [...]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
slice := numbers4[4:6:8] 
fmt.Printf("%d
", cap(slice))

Why is cap(slice) equal to 4?

I used to thought that should be 2.

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Answer 1

The capacity is the number of elements in the underlying array (beginning at the element referred to by the slice pointer).

from Go Slices: usage and internals.

Basically, it means cap != len.
So, the slice starts at #4, and finishes at #8, hence, cap is 8 - 4 = 4.