Go Slice Expressions: Difference between revisions

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Slice expressions can be used on array or other slices.
Slice expressions can be used on array or other slices.


A slice expression applied to a slice creates a new slice that shares the underlying array with the original slice.
A slice expression applied to a slice creates a '''new''' slice that '''shares the underlying array''' with the original slice.


<syntaxhighlight lang='go'>
<syntaxhighlight lang='go'>

Revision as of 02:55, 19 August 2024

Internal

TODO

Overview

Slice expressions can be used on array or other slices.

A slice expression applied to a slice creates a new slice that shares the underlying array with the original slice.

ss := make([]int, 10) // declare a slice with length and capacity 10, initialized with 0
ss2 := ss[3:6]

    ┌─────────────────────┐
 ss │pointer,len=10,cap=10│
    └──│──────│──────│────┘
       │      └──────┴──────────────────────────┐
       └──────────────────────┐                 │
                              ▼                 ▼
                             ┌─┬─┬─┬─┬─┬─┬─┬─┬─┬─┐
             derlying array  └─┴─┴─┴─┴─┴─┴─┴─┴─┴─┘
                              0 1 2 3 4 5 6 7 8 9
                                    ▲   ▲       ▲
        ┌───────────────────────────┘   │       │
        │      ┌────────────────────────┘       │
        │      │     ┌──────────────────────────┘
    ┌───│──────│─────│────┐    
ss2 │ pointer,len=3,cap=7 │
    └─────────────────────┘

The slice expression creates a different slice that provides access to the elements with indexes 3, 4, 5 of the underlying array. Both slices ss and ss2 provide access to those elements and changes operated via one slice are visible to the other.

The length of the second slice is the number of elements defined by the slice expression (3). However, since the slices share the same underlying array, the capacity of the second slice is the number of elements from the element with index 3 to the end of the underlying array: 7.