CODEWITHSUNDEEP
go
Rekt
Rekt

Reputation: 399

How to iterate on slices, 4 items at a time

How do I iterate through a Go slice 4 items at a time.

lets say I have [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]

I want a for loop to be able to get

[1,2,3,4] //First Iteration
[5,6,7,8] //Second Iteration
[9,10,11,12] //Third Iteration
[13,14,15,] // Fourth Iteration

I can do this in java and python but for golang I really dont have an idea.

Upvotes: 3

Views: 2317

Answers (2)

peterSO
peterSO

Reputation: 166529

How To Iterate on Slices in Go, Iterating 4 items at a time. I want a for loop.

In Go, readability is paramount. First we read the normal path, then we read the exception/error paths.

We write the normal path.

n := 4
for i := 0; i < len(s); i += n {
    ss := s[i : i+n]
    fmt.Println(ss)
}

We use n for the stride value throughout.

We write a little tweak that doesn't disturb the normal path to handle an exception, the end of the slice.

if n > len(s)-i {
    n = len(s) - i
}

For example,

package main

import "fmt"

func main() {
    s := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
    n := 4
    for i := 0; i < len(s); i += n {
        if n > len(s)-i {
            n = len(s) - i
        }
        ss := s[i : i+n]
        fmt.Println(ss)
    }
}

Playground: https://play.golang.org/p/Vtpig2EeXB7

Output:

[1 2 3 4]
[5 6 7 8]
[9 10 11 12]
[13 14 15]

Upvotes: 3

PatrickMahomes
PatrickMahomes

Reputation: 934

For example,

package main

import "fmt"

func main() {
    slice := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
    for i := 0; i < len(slice); i += 4 {
        var section []int
        if i > len(slice)-4 {
            section = slice[i:]
        } else {
            section = slice[i : i+4]
        }
        fmt.Println(section)
    }
}

Playground: https://play.golang.org/p/kf7_OJcP13t

Output:

[1 2 3 4]
[5 6 7 8]
[9 10 11 12]
[13 14 15]

Upvotes: 3

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