Type Conversion - Scan

If the previous complex type conversion functionality is not sufficient, you can explore the Scan conversion method. This method can convert arbitrary parameters to struct/struct arrays/map/map arrays and automatically recognize and execute conversion based on the developer‘s input target parameters.

The method is defined as follows:

// Scan automatically calls MapToMap, MapToMaps, Struct or Structs function according to
// the type of parameter `pointer` to implement the converting.
// It calls function MapToMap if `pointer` is type of *map to do the converting.
// It calls function MapToMaps if `pointer` is type of *[]map/*[]*map to do the converting.
// It calls function Struct if `pointer` is type of *struct/**struct to do the converting.
// It calls function Structs if `pointer` is type of *[]struct/*[]*struct to do the converting.
func Scan(params interface{}, pointer interface{}, mapping ...map[string]string) (err error)

Let‘s look at a few examples for a quick understanding.

Auto-recognition Conversion Struct

package main

import (
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/util/gconv"
)

func main() {
    type User struct {
        Uid  int
        Name string
    }
    params := g.Map{
        "uid":  1,
        "name": "john",
    }
    var user *User
    if err := gconv.Scan(params, &user); err != nil {
        panic(err)
    }
    g.Dump(user)
}

After execution, the output result is:

{
    Uid:  1,
    Name: "john",
}

Auto-recognition Conversion Struct Array

package main

import (
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/util/gconv"
)

func main() {
    type User struct {
        Uid  int
        Name string
    }
    params := g.Slice{
        g.Map{
            "uid":  1,
            "name": "john",
        },
        g.Map{
            "uid":  2,
            "name": "smith",
        },
    }
    var users []*User
    if err := gconv.Scan(params, &users); err != nil {
        panic(err)
    }
    g.Dump(users)
}

After execution, the terminal output is:

[
    {
        Uid:  1,
        Name: "john",
    },
    {
        Uid:  2,
        Name: "smith",
    },
]

Auto-recognition Conversion to Map

package main

import (
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/util/gconv"
)

func main() {
    var (
        user   map[string]string
        params = g.Map{
            "uid":  1,
            "name": "john",
        }
    )
    if err := gconv.Scan(params, &user); err != nil {
        panic(err)
    }
    g.Dump(user)
}

After execution, the output result is:

{
    "uid":  "1",
    "name": "john",
}

Auto-recognition Conversion Map Array

package main

import (
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/util/gconv"
)

func main() {
    var (
        users  []map[string]string
        params = g.Slice{
            g.Map{
                "uid":  1,
                "name": "john",
            },
            g.Map{
                "uid":  2,
                "name": "smith",
            },
        }
    )
    if err := gconv.Scan(params, &users); err != nil {
        panic(err)
    }
    g.Dump(users)
}

After execution, the output result is:

[
    {
        "uid":  "1",
        "name": "john",
    },
    {
        "uid":  "2",
        "name": "smith",
    },
]