英文:
Accessing data in nested arrays & objects with Go
问题
我正在尽力将一些JSON数据解组成可用的形式，但似乎无法成功。数据如下：
{
"series": [
{
"series_id": "PET.EMD_EPD2D_PTE_NUS_DPG.W",
"name": "U.S. No 2 Diesel Retail Prices, Weekly",
"units": "Dollars per Gallon",
"updated": "2013-09-27T07:21:57-0400",
"data": [
[
"20130923",
"3.949"
],
[
"20130916",
"3.974"
]
]
}
]
}
我试图将data下的数组存入一个变量中，以便可以遍历它们并执行类似以下的操作：
if data[i][0] == "20130923" {
fuelPrice.Price == data[i][1]
}
我尝试将数据解组成一个结构体，但无法解决series的问题...也就是说，我无法解决如何处理嵌套数组的问题。以下类似的尝试都不起作用：
type Series struct {
SeriesId string
Name string
Data [][]string
}
type RawFuelPrice struct {
Series []Series
Data []interface{}[]
}
另外，如果我解组成interface{}，我也不知道如何访问数据...
我肯定是个初学者。感谢你的时间和努力。
英文:
I'm doing my best to unmarshall some json data into usable form in Go, but can't seem to get it. The data is:
{
"series": [
{
"series_id": "PET.EMD_EPD2D_PTE_NUS_DPG.W",
"name": "U.S. No 2 Diesel Retail Prices, Weekly",
"units": "Dollars per Gallon",
"updated": "2013-09-27T07:21:57-0400",
"data": [
[
"20130923",
"3.949"
],
[
"20130916",
"3.974"
]
]
}
]
}
I'm trying to get the arrays under data into a variable, so I can loop through them and do something like:
if data[i][0] == "20130923" {
fuelPrice.Price == data[i][1]
}
I've tried to unmarshall the data into a struct but I can't figure out how to get past series... ie I can't figure out how to do nested arrays. Things like these don't work:
type Series struct {
SeriesId string
Name string
Data [][]string
}
type RawFuelPrice struct {
Series []Series
Data []interface{}[]
}
Also if I unmarshal into an interface{}, I can't figure out how to access the data...
I'm definitely a beginner. Thanks for your time and effort.
答案1
得分: 1
你的代码没问题，除了RawFuelPrice结构体的Data成员。我认为那个语法是无效的，并且在JSON数据块的顶层没有Data属性。
不过，你可以这样提取数据：
var rfp RawFuelPrice
json.Unmarshal(input, &rfp)
for _, s := range rfp.Series {
fmt.Println("Name", s.Name)
for _, d := range s.Data {
fmt.Println("\tdate:", d[0])
fmt.Println("\tprice:", d[1])
}
fmt.Println()
}
不过，你可能需要检查所有的数据是否都存在。
Go Playground链接：http://play.golang.org/p/C47lZJ_L0o
英文:
Your code is just fine- except for the Data member of the RawFuelPrice struct. I don't think that syntax is valid, and there's no Data attribute at the top level of of the JSON blob.
That said, this is how you'd get the data out:
var rfp RawFuelPrice
json.Unmarshal(input, &rfp)
for _,s := range rfp.Series {
fmt.Println("Name",s.Name)
for _,d := range s.Data {
fmt.Println("\tdate:",d[0])
fmt.Println("\tprice:",d[1])
}
fmt.Println()
}
Although you'd probably want to check that all the data was there.
Go Playground link: http://play.golang.org/p/C47lZJ_L0o
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