how to insert data into multi dimension array in golang?

Question

I have a dynamic multi dimension array, I need to fill dynamically from the loop. how can i define the array and fill the data.

Here is the code which im trying

var arrDetails[][]string
var index int = 0
for _, orderdetails := range ordersfromdb {
    arrDetails[index]["OrderNumber"] = "001"
    arrDetails[index]["customernum"] = "cust_001"
    arrDetails[index]["orderstatus"] = "open"
    arrDetails[index]["orderprice"] = "200"
    index++
}

error which im facing:

non-integer slice index "OrderNumber"
non-integer slice index "customernum"
non-integer slice index "orderstatus"
non-integer slice index "orderprice"

I have done the same in php and works perfect:

for ($i=0;$i<5:$i++)
{
     $arr_orderdetails[$i]["OrderNumber"] = "001";
     $arr_orderdetails[$i]["customernum"] = "cust_001";
     $arr_orderdetails[$i]["orderstatus"] = "open";
     $arr_orderdetails[$i]["orderprice"] = "200";
}

I'm new to golang, not able to find where it is going wrong, any help much appreciated.

Thanks :)

Slices are indexed using integer numbers, and you used a string value. That obviously won't work. Maybe what you want is a slice of maps []map[string]float64 or a slice of structs describing your object? — icza
– icza, Commented Oct 16, 2018 at 8:56
"I'm very new to [Go]" So take The Tour of Go and start with the simpler things until you are comfortable with them and jump into dynamic multidimensional stuff later. — Volker
– Volker, Commented Oct 16, 2018 at 9:01
"not able to find where it is going wrong" You cannot use strings as slice indices in Go. Go is neither PHP nor JavaScript. You should try a map. — Volker
– Volker, Commented Oct 16, 2018 at 9:28

Alex Medveshchek · Accepted Answer · 2018-10-16 12:22:14Z

Let's consider this solution:

arrDetails := map[int]map[string]string{}

index := 0
for _, orderdetails := range ordersfromdb {
    arrDetails[index] = map[string]string{} // you have to initialize map

    arrDetails[index]["OrderNumber"] = "001"
    arrDetails[index]["customernum"] = "cust_001"
    arrDetails[index]["orderstatus"] = "open"
    arrDetails[index]["orderprice"] = "200"

    index++
}

To convert results to json (as I saw you question in comment to @liao yu's answer), we should learn something more about tags:

import (
    "encoding/json"
    "fmt"
)

type OrderDetails struct {
    Number   string `json:"number"`
    Customer string `json:"customer"`
    Status   string `json:"status"`
    Price    string `json:"price"`
}

func main() {
    ordersfromdb := []int{1, 2, 3}

    var arrDetails []OrderDetails
    for _, v := range ordersfromdb {
        arrDetails = append(arrDetails, OrderDetails{
            Number:   fmt.Sprintf("order_number_%v", v),
            Customer: fmt.Sprintf("customer_%v", v),
            Status:   fmt.Sprintf("order_status_%v", v),
            Price:    fmt.Sprintf("$%v", v),
        })
    }

    data, err := json.Marshal(arrDetails)
    if err != nil {
        panic(err)
    }
    fmt.Println(string(data))
}

See it on playground: https://play.golang.org/p/IA0G53YX_dZ

btc user · Accepted Answer · 2018-10-16 10:27:55Z

0

As per volker suggestion in the comment, I'm fill the multi dimensional array as below

arrDetails[index][0] = "001"
arrDetails[index][1] = "cust_001"
arrDetails[index][2] = "open"
arrDetails[index][3] = "200"

answered Oct 16, 2018 at 10:27

btc user

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Comments

liao yu · Accepted Answer · 2018-10-16 10:58:29Z

0

you can try this:

import "fmt"

func main() {

    var arrDetails []map[string]string
    var index int = 0

    //for _, orderdetails := range ordersfromdb {
    for i:=0; i<5;i++ {
        detail := make(map[string]string)

        detail["OrderNumber"] = "001"
        detail["customernum"] = "cust_001"
        detail["orderstatus"] = "open"
        detail["orderprice"] = "200"
        arrDetails = append(arrDetails, detail)

        index++
    }
    fmt.Printf("Hello, playground %+v", arrDetails )
}

answered Oct 16, 2018 at 10:58

liao yu

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1 Comment

btc user Over a year ago

can we covert the result to json? json.Marshal?

saddam · Accepted Answer · 2018-10-16 16:52:27Z

0

As you defined here your arrDetails variable as multidimentional slice as [][]string.It means you can not assign a string into its keys while you can assign string as a value.

You can do your code like below I mentioned.

package main

import (
    "fmt"
)

func main() {
  var arrDetails [][]string
  var s []string
  var index int
  for i:=0; i<5;i++ {
     s = []string{"001", "cust_001", "open", "200"}
     arrDetails = append(arrDetails, s)
     index++
  } 
fmt.Printf("Hello, playground %+v", arrDetails )
}

Or if you want keys and value pair then you've to use map as:

var arrDetails map[string]string

edited Oct 16, 2018 at 16:52

answered Oct 16, 2018 at 9:37

saddam

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