How to populate a nested golang struct, which contains an array of structs

Question

So I've been trying to populate this monster of a struct I created, but with no success.

type Initial_Load struct {
    Chapters []struct {
        Name    string `Chapter Name`
        PageNum int    `Number of Page"`
        Pages   []struct {
            Description string `Page Description`
            PageNumber  int    `Page Number`
            Source      string `Page Source`
        }
    }
    NumChapters int `Total number of chapters`
}

Here's the JSON that this struct is modeling

{
   "Num_Chapters": 2,
   "Chapters": [
      {
         "Name": "Pilot",
         "Page_Num": 2,
         "Pages": [
            {
               "Page_Number": 1,
               "Source": "local.com",
               "Description": "First Page"
            },
            {
               "Page_Number": 2,
               "Source": "local.com",
               "Description": "Second Page"
            }
         ]
      },
      {
         "Name": "Chapter2",
         "Page_Num": 2,
         "Pages": [
            {
               "Page_Number": 1,
               "Source": "local.com",
               "Description": "First Page"
            },
            {
               "Page_Number": 2,
               "Source": "local.com",
               "Description": "Second Page"
            }
         ]
      },
      {
         "Name": "Chapter3",
         "Page_Num": 2,
         "Pages": [
            {
               "Page_Number": 1,
               "Source": "local.com",
               "Description": "First Page"
            },
            {
               "Page_Number": 2,
               "Source": "local.com",
               "Description": "Second Page"
            }
         ]
      }
   ]
}

There's of answered questions about populating nested structs, but I haven't found one which contains an array of structs. I know this is probably very simple, but I just can't figure it out. Thanks.

Andy Schweig · Accepted Answer · 2016-03-09 04:13:00Z

4

You may need to define those inner structs as types. This works:

type Page struct {
    Description string
    PageNumber  int
    Source      string
}

type Chapter struct {
    Name    string
    PageNum int
    Pages   []Page
}

type Initial_Load struct {
    Chapters    []Chapter
    NumChapters int
}

var x Initial_Load = Initial_Load{
    Chapters: []Chapter{
        {
            Name:    "abc",
            PageNum: 3,
            Pages: []Page{
                {
                    Description: "def",
                    PageNumber:  3,
                    Source:      "xyz",
                },
                {
                    Description: "qrs",
                    PageNumber:  5,
                    Source:      "xxx",
                },
            },
        },
    },
    NumChapters: 1,
}

I only put in 1 chapter, but you get the idea.

answered Mar 9, 2016 at 4:13

Andy Schweig

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1 Comment

Maz Baig Over a year ago

Thanks! This is the part I was having trouble with: Pages: []Page{{Description: "def",PageNumber: 3,Source: "xyz",},{ Description: "qrs",PageNumber: 5,Source: "xxx", }

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