How to create a slice of objects using for loop

Question

Code:

    files, err := ioutil.ReadDir(".")
    elements := make(map[string]interface{})
    for _, file := range files {
        elements["name"] = file.Name()
        elements["directory"] = file.IsDir()
        elements["size"] = file.Size()
    }
    ctxt.JSON(http.StatusOK, elements)

Here I'm getting a response with only last file details.
How can I create a slice of objects, that means I want all files details in the response.

You should try using a concrete struct, it is a much better programming experience then having to deal with maps of empty interfaces... That said, in each iteration you need to create a map and aggregate those maps into a slice, that way you get all the files details. (play.golang.com/p/xjDrWwvtDZC) — mkopriva
– mkopriva, Commented Nov 11, 2019 at 7:01
Work through the Tour of Go once more for basic language constructs. — Volker
– Volker, Commented Nov 11, 2019 at 7:10

Naveen · Accepted Answer · 2019-11-11 07:32:42Z

2

Something like this:

files, err := ioutil.ReadDir(".")
elements := []map[string]interface{}{}
for _, file := range files {
    elements = append(elements, map[string]interface{}{
        "name":      file.Name(),
        "directory": file.IsDir(),
        "size":      file.Size()})
}
ctxt.JSON(http.StatusOK, elements)

edited Nov 11, 2019 at 7:32

Naveen

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answered Nov 11, 2019 at 7:07

Clément

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1 Comment

Clément Over a year ago

I also agree with @mkopriva about using struct, but that's up to you.

ksaritek · Accepted Answer · 2019-11-11 08:47:19Z

0

instead of append, you can create the array with size

package main
import (
    "fmt"
    "io/ioutil"
)

func main() {
    files, _ := ioutil.ReadDir(".")
    elements := make([]map[string]interface{}, len(files))
    for i, file := range files {

        e := map[string]interface{}{
            "name":      file.Name(),
            "directory": file.IsDir(),
            "size":      file.Size(),
        }

        elements[i] = e
    }

    for i, e := range elements {
        fmt.Println(i, e)
    }
}

answered Nov 11, 2019 at 8:47

ksaritek

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