Slice
This Go program is a tutorial that demonstrates various concepts related to slices, a dynamic array-like data structure in Go. The code covers topics such as slice creation, modification, appending, copying, and working with two-dimensional slices.
Below is a detailed explanation of the code:
package main
import (
"fmt"
"slices"
)
func main() {
// Declare an uninitialized slice of strings
var s []string
// Print the uninitialized slice, its nil status, and its length
fmt.Println("uninit:", s, s == nil, len(s) == 0) // Output: uninit: [] true true
// Create an empty slice of strings with a length of 3 and a capacity of 3
s = make([]string, 3)
fmt.Println("emp:", s, "len:", len(s), "cap:", cap(s)) // Output: emp: [ ] len: 3 cap: 3
// Set values for the first three elements of the slice
s[0] = "a"
s[1] = "b"
s[2] = "c"
fmt.Println("set:", s) // Output: set: [a b c]
// Access the third element of the slice
fmt.Println("get:", s[2]) // Output: get: c
// Print the length of the slice
fmt.Println("len:", len(s)) // Output: len: 3
// Append new elements to the slice
s = append(s, "d")
s = append(s, "e", "f")
fmt.Println("apd:", s) // Output: apd: [a b c d e f]
// Create a new slice `c` with the same length as `s` and copy elements from `s` to `c`
c := make([]string, len(s))
copy(c, s)
fmt.Println("cpy:", c) // Output: cpy: [a b c d e f]
// Slice a portion of `s` from index 2 (inclusive) to index 5 (exclusive)
l := s[2:5]
fmt.Println("sl1:", l) // Output: sl1: [c d e]
// Slice `s` from the beginning (inclusive) to index 5 (exclusive)
l = s[:5]
fmt.Println("sl2:", l) // Output: sl2: [a b c d e]
// Slice `s` from index 2 (inclusive) to the end
l = s[2:]
fmt.Println("sl3:", l) // Output: sl3: [c d e f]
// Declare and initialize a slice `t` with values in a single line
t := []string{"g", "h", "i"}
fmt.Println("dcl:", t) // Output: dcl: [g h i]
// Declare another slice `t2` with the same values as `t`
t2 := []string{"g", "h", "i"}
// Use the `slices.Equal` function to check if `t` and `t2` are equal
if slices.Equal(t, t2) {
fmt.Println("t == t2") // Output: t == t2
}
// Create a 2-dimensional slice of integers
twoD := make([][]int, 3)
for i := 0; i < 3; i++ {
innerLen := i + 1
twoD[i] = make([]int, innerLen)
for j := 0; j < innerLen; j++ {
twoD[i][j] = i + j
}
}
fmt.Println("2d: ", twoD) // Output: 2d: [[0] [1 2] [2 3 4]]
}
Output
uninit: [] true true
emp: [ ] len: 3 cap: 3
set: [a b c]
get: c
len: 3
apd: [a b c d e f]
cpy: [a b c d e f]
sl1: [c d e]
sl2: [a b c d e]
sl3: [c d e f]
dcl: [g h i]
t == t2
2d: [[0] [1 2] [2 3 4]]
Let's break down the code step by step:
Package Import:
package main import ( "fmt" "slices" )
The
main
package is the entry point for the executable.It imports the "fmt" package for formatted I/O and a custom "slices" package (presumably defined elsewhere) for a function called
Equal
.
Main Function:
func main() { // ... }
The
main
function is the starting point of the program.
Slice Declaration and Initialization:
var s []string fmt.Println("uninit:", s, s == nil, len(s) == 0) s = make([]string, 3) fmt.Println("emp:", s, "len:", len(s), "cap:", cap(s))
Declares an uninitialized slice
s
and prints its properties.Initializes
s
with a length of 3 usingmake
, and prints the slice along with its length and capacity.
Slice Modification:
s[0] = "a" s[1] = "b" s[2] = "c" fmt.Println("set:", s) fmt.Println("get:", s[2]) fmt.Println("len:", len(s))
Sets values in the slice
s
, prints the modified slice, retrieves and prints an element, and prints the length of the slice.
Slice Appending:
s = append(s, "d") s = append(s, "e", "f") fmt.Println("apd:", s)
Appends elements "d", "e", and "f" to the slice
s
using theappend
function, and prints the resulting slice.
Slice Copying:
c := make([]string, len(s)) copy(c, s) fmt.Println("cpy:", c)
Creates a new slice
c
with the same length ass
usingmake
.Copies the elements of
s
toc
using thecopy
function and prints the copied slice.
Slice Slicing:
l := s[2:5] fmt.Println("sl1:", l) l = s[:5] fmt.Println("sl2:", l) l = s[2:] fmt.Println("sl3:", l)
Demonstrates various ways to create sub-slices of the original slice
s
and prints the results.
Slice Declaration and Initialization with Literal Values:
t := []string{"g", "h", "i"} fmt.Println("dcl:", t)
Declares and initializes a slice
t
with literal values "g", "h", and "i", and prints the slice.
Custom Slice Equality Check:
t2 := []string{"g", "h", "i"} if slices.Equal(t, t2) { fmt.Println("t == t2") }
Uses a custom function
Equal
from the "slices" package to check if slicest
andt2
are equal and prints a message accordingly.
Two-Dimensional Slice:
twoD := make([][]int, 3) // ... (nested loop to initialize values) fmt.Println("2d: ", twoD)
Creates a two-dimensional slice
twoD
with three inner slices.Initializes values in the two-dimensional slice using a nested loop.
Prints the two-dimensional slice.
This tutorial covers fundamental concepts related to slices in Go, including creation, modification, appending, copying, slicing, and working with two-dimensional slices. The custom Equal
function demonstrates how you can extend functionality by creating your own utility functions.
Last updated
Was this helpful?