blocks|key|639711|text|在引号中传递一个值会使其看起来像字符串。将"price":"3460.00"更改为"price":3460.00，一切都会正常工作。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|639712|如果您不能去掉引号，则必须使用strconv.ParseFloat自己解析它|639713|package+main

import+(
++++"encoding/json"
++++"fmt"
++++"strconv"
)

type+Product+struct+{
++++Name+++++++string
++++Price++++++string
++++PriceFloat+float64
}

func+main()+{
++++s+:=+`{"name":"Galaxy+Nexus",+"price":"3460.00"}`
++++var+pro+Product
++++err+:=+json.Unmarshal([]byte(s),+&pro)
++++if+err+==+nil+{
++++++++pro.PriceFloat,+err+=+strconv.ParseFloat(pro.Price,+64)
++++++++if+err+!=+nil+{+fmt.Println(err)+}
++++++++fmt.Printf("%25%2Bv\n",+pro)
++++}+else+{
++++++++fmt.Println(err)
++++++++fmt.Printf("%25%2Bv\n",+pro)
++++}
}|code-block|syntax|javascript|639714|entityMap^0|L|H|15|F|0|F|I|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

Passing a value in quotation marks make that look like string. Change <code>"price":"3460.00"</code> to <code>"price":3460.00</code> and everything works fine.

If you can't drop the quotations marks you have to parse it by yourself, using <code>strconv.ParseFloat</code>:

<pre><code>package main

import (
 "encoding/json"
 "fmt"
 "strconv"
)

type Product struct {
 Name string
 Price string
 PriceFloat float64
}

func main() {
 s := `{"name":"Galaxy Nexus", "price":"3460.00"}`
 var pro Product
 err := json.Unmarshal([]byte(s), &amp;pro)
 if err == nil {
 pro.PriceFloat, err = strconv.ParseFloat(pro.Price, 64)
 if err != nil { fmt.Println(err) }
 fmt.Printf("%+v\n", pro)
 } else {
 fmt.Println(err)
 fmt.Printf("%+v\n", pro)
 }
}
</code></pre>

blocks|key|425334|text|答案要简单得多。只需添加，告诉JSON+interpeter这是一个带有,string的字符串编码的float64+(注意，我只更改了Price的定义)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|425335|package+main

import+(
++++"encoding/json"
++++"fmt"
)

type+Product+struct+{
++++Name++string
++++Price+float64+`json:",string"`
}

func+main()+{
++++s+:=+`{"name":"Galaxy+Nexus",+"price":"3460.00"}`
++++var+pro+Product
++++err+:=+json.Unmarshal([]byte(s),+&pro)
++++if+err+==+nil+{
++++++++fmt.Printf("%25%2Bv\n",+pro)
++++}+else+{
++++++++fmt.Println(err)
++++++++fmt.Printf("%25%2Bv\n",+pro)
++++}
}|code-block|syntax|javascript|425336|entityMap^0|10|7|1V|5|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

The answer is considerably less complicated. Just add tell the JSON interpeter it's a string encoded float64 with <code>,string</code> (note that I only changed the <code>Price</code> definition):

<pre><code>package main

import (
 "encoding/json"
 "fmt"
)

type Product struct {
 Name string
 Price float64 `json:",string"`
}

func main() {
 s := `{"name":"Galaxy Nexus", "price":"3460.00"}`
 var pro Product
 err := json.Unmarshal([]byte(s), &amp;pro)
 if err == nil {
 fmt.Printf("%+v\n", pro)
 } else {
 fmt.Println(err)
 fmt.Printf("%+v\n", pro)
 }
}
</code></pre>

blocks|key|425384|text|我只想让您知道，您可以使用json.decode来完成此任务，而无需使用Unmarshal。这是Go+Playground|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|425385|package+main

import+(
++++"encoding/json"
++++"fmt"
++++"strings"
)

type+Product+struct+{
++++Name++string+`json:"name"`
++++Price+float64+`json:"price,string"`
}

func+main()+{
++++s+:=+`{"name":"Galaxy+Nexus","price":"3460.00"}`
++++var+pro+Product
++++err+:=+json.NewDecoder(strings.NewReader(s)).Decode(&pro)
++++if+err+!=+nil+{
++++++++fmt.Println(err)
++++++++return
++++}
++++fmt.Println(pro)
}|code-block|syntax|javascript|425386|entityMap|0|LINK|mutability|MUTABLE|url|https://play.golang.org/p/qnjfVVcYYZ^0|D|B|10|9|1C|D|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

Just letting you know that you can do this without <code>Unmarshal</code> and use <code>json.decode</code>. Here is <a href="https://play.golang.org/p/qnjfVVcYYZ" rel="noreferrer">Go Playground</a>

<pre><code>package main

import (
 "encoding/json"
 "fmt"
 "strings"
)

type Product struct {
 Name string `json:"name"`
 Price float64 `json:"price,string"`
}

func main() {
 s := `{"name":"Galaxy Nexus","price":"3460.00"}`
 var pro Product
 err := json.NewDecoder(strings.NewReader(s)).Decode(&amp;pro)
 if err != nil {
 fmt.Println(err)
 return
 }
 fmt.Println(pro)
}
</code></pre>

blocks|key|425510|text|避免将字符串转换为[]byte：b+:=+[]byte(s)。它分配一个新的内存空间，并将整个内容复制到其中。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|425511|strings.NewReader界面更好。下面是来自godoc的代码：|425512|package+main

import+(
++++"encoding/json"
++++"fmt"
++++"io"
++++"log"
++++"strings"
)

func+main()+{
++++const+jsonStream+=+`
++++{"Name":+"Ed",+"Text":+"Knock+knock."}
++++{"Name":+"Sam",+"Text":+"Who's+there?"}
++++{"Name":+"Ed",+"Text":+"Go+fmt."}
++++{"Name":+"Sam",+"Text":+"Go+fmt+who?"}
++++{"Name":+"Ed",+"Text":+"Go+fmt+yourself!"}
`
++++type+Message+struct+{
++++++++Name,+Text+string
++++}
++++dec+:=+json.NewDecoder(strings.NewReader(jsonStream))
++++for+{
++++++++var+m+Message
++++++++if+err+:=+dec.Decode(&m);+err+==+io.EOF+{
++++++++++++break
++++++++}+else+if+err+!=+nil+{
++++++++++++log.Fatal(err)
++++++++}
++++++++fmt.Printf("%25s:+%25s\n",+m.Name,+m.Text)
++++}
}|code-block|syntax|javascript|425513|entityMap^0|G|E|0|0|H|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|U|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

Avoid converting a string to []byte: <code>b := []byte(s)</code>. It allocates a new memory space and copy the whole the content into it.

<code>strings.NewReader</code> interface is better. Below is the code from godoc:

<pre><code>package main

import (
 "encoding/json"
 "fmt"
 "io"
 "log"
 "strings"
)

func main() {
 const jsonStream = `
 {"Name": "Ed", "Text": "Knock knock."}
 {"Name": "Sam", "Text": "Who's there?"}
 {"Name": "Ed", "Text": "Go fmt."}
 {"Name": "Sam", "Text": "Go fmt who?"}
 {"Name": "Ed", "Text": "Go fmt yourself!"}
`
 type Message struct {
 Name, Text string
 }
 dec := json.NewDecoder(strings.NewReader(jsonStream))
 for {
 var m Message
 if err := dec.Decode(&amp;m); err == io.EOF {
 break
 } else if err != nil {
 log.Fatal(err)
 }
 fmt.Printf("%s: %s\n", m.Name, m.Text)
 }
}
</code></pre>

I need to decode a JSON string with the float number like:

<pre><code>{"name":"Galaxy Nexus", "price":"3460.00"}
</code></pre>

I use the Golang code below:

<pre><code>package main

import (
 "encoding/json"
 "fmt"
)

type Product struct {
 Name string
 Price float64
}

func main() {
 s := `{"name":"Galaxy Nexus", "price":"3460.00"}`
 var pro Product
 err := json.Unmarshal([]byte(s), &amp;pro)
 if err == nil {
 fmt.Printf("%+v\n", pro)
 } else {
 fmt.Println(err)
 fmt.Printf("%+v\n", pro)
 }
}
</code></pre>

When I run it, get the result:

<pre><code>json: cannot unmarshal string into Go value of type float64
{Name:Galaxy Nexus Price:0}
</code></pre>

I want to know how to decode the JSON string with type convert.

How to decode JSON with type convert from string to float64

JSON

我需要解码一个带有浮点数的JSON字符串，如下所示：{"name":"Galaxy Nexus", "price":"3460.00"}我使用下面的Golang代码：package mainimport (    "encoding/json"    "fmt")type Product struct {    Nam...

问如何使用string到float64类型转换解码JSON
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