・0 pv・31 min read
GO JSONのパース方法についての備忘録
はじめに
ネストが深くて配列もあるJSONのパース方法に悩んだので備忘録として残します。
環境
- macOS Monterey 12.3.1
- Go 1.18.1
パースしようとしたJSON
YahooFinanceAPIのレスポンスを例に説明していきます。
構造としては"quoteResponse"の中に"error","result"があり、
"result"は配列でその中には"ask"〜"twoHundredDayAverageChangePercent"があります。
JSONのレスポンス例
{
"quoteResponse": {
"error": null,
"result": [
{
"ask": 117.27,
"askSize": 8,
"averageDailyVolume10Day": 233119800,
"averageDailyVolume3Month": 170533131,
"bid": 117.25,
"bidSize": 22,
"bookValue": 4.218,
"currency": "USD",
"displayName": "Apple",
"dividendDate": 1597276800,
"earningsTimestamp": 1596126600,
"earningsTimestampEnd": 1604318400,
"earningsTimestampStart": 1603882740,
"epsCurrentYear": 3.23,
"epsForward": 3.86,
"epsTrailingTwelveMonths": 3.296,
"esgPopulated": false,
"exchange": "NMS",
"exchangeDataDelayedBy": 0,
"exchangeTimezoneName": "America/New_York",
"exchangeTimezoneShortName": "EDT",
"fiftyDayAverage": 112.823425,
"fiftyDayAverageChange": 4.4965744,
"fiftyDayAverageChangePercent": 0.03985497,
"fiftyTwoWeekHigh": 137.98,
"fiftyTwoWeekHighChange": -20.659996,
"fiftyTwoWeekHighChangePercent": -0.14973181,
"fiftyTwoWeekLow": 53.1525,
"fiftyTwoWeekLowChange": 64.167496,
"fiftyTwoWeekLowChangePercent": 1.2072338,
"fiftyTwoWeekRange": "53.1525 - 137.98",
"financialCurrency": "USD",
"firstTradeDateMilliseconds": 345479400000,
"forwardPE": 30.393784,
"fullExchangeName": "NasdaqGS",
"gmtOffSetMilliseconds": -14400000,
"language": "en-US",
"longName": "Apple Inc.",
"market": "us_market",
"marketCap": 2006465249280,
"marketState": "POST",
"messageBoardId": "finmb_24937",
"postMarketChange": -0.25,
"postMarketChangePercent": -0.2130924,
"postMarketPrice": 117.07,
"postMarketTime": 1599686591,
"priceEpsCurrentYear": 36.32198,
"priceHint": 2,
"priceToBook": 27.81413,
"quoteSourceName": "Nasdaq Real Time Price",
"quoteType": "EQUITY",
"region": "US",
"regularMarketChange": 4.5,
"regularMarketChangePercent": 3.9886546,
"regularMarketDayHigh": 119.14,
"regularMarketDayLow": 115.26,
"regularMarketDayRange": "115.26 - 119.14",
"regularMarketOpen": 117.26,
"regularMarketPreviousClose": 112.82,
"regularMarketPrice": 117.32,
"regularMarketTime": 1599681602,
"regularMarketVolume": 168404235,
"sharesOutstanding": 17102499840,
"shortName": "Apple Inc.",
"sourceInterval": 15,
"symbol": "AAPL",
"tradeable": false,
"trailingAnnualDividendRate": 0.782,
"trailingAnnualDividendYield": 0.0069313953,
"trailingPE": 35.59466,
"triggerable": true,
"twoHundredDayAverage": 85.99835,
"twoHundredDayAverageChange": 31.321648,
"twoHundredDayAverageChangePercent": 0.3642122
},
{
"ask": 211.63,
"askSize": 9,
"averageDailyVolume10Day": 43250000,
"averageDailyVolume3Month": 35562815,
"bid": 211.25,
"bidSize": 9,
"bookValue": 15.626,
"currency": "USD",
"displayName": "Microsoft",
"dividendDate": 1599696000,
"earningsTimestamp": 1595434164,
"earningsTimestampEnd": 1603742400,
"earningsTimestampStart": 1603310400,
"epsCurrentYear": 6.46,
"epsForward": 7.34,
"epsTrailingTwelveMonths": 5.76,
"esgPopulated": false,
"exchange": "NMS",
"exchangeDataDelayedBy": 0,
"exchangeTimezoneName": "America/New_York",
"exchangeTimezoneShortName": "EDT",
"fiftyDayAverage": 212.50658,
"fiftyDayAverageChange": -1.2165833,
"fiftyDayAverageChangePercent": -0.0057249204,
"fiftyTwoWeekHigh": 232.86,
"fiftyTwoWeekHighChange": -21.570007,
"fiftyTwoWeekHighChangePercent": -0.092630796,
"fiftyTwoWeekLow": 132.52,
"fiftyTwoWeekLowChange": 78.76999,
"fiftyTwoWeekLowChangePercent": 0.59440076,
"fiftyTwoWeekRange": "132.52 - 232.86",
"financialCurrency": "USD",
"firstTradeDateMilliseconds": 511108200000,
"forwardPE": 28.786102,
"fullExchangeName": "NasdaqGS",
"gmtOffSetMilliseconds": -14400000,
"language": "en-US",
"longName": "Microsoft Corporation",
"market": "us_market",
"marketCap": 1598968692736,
"marketState": "POST",
"messageBoardId": "finmb_21835",
"postMarketChange": -61.5672,
"postMarketChangePercent": -29.13872,
"postMarketPrice": 149.7228,
"postMarketTime": 1599686588,
"priceEpsCurrentYear": 32.707428,
"priceHint": 2,
"priceToBook": 13.521694,
"quoteSourceName": "Nasdaq Real Time Price",
"quoteType": "EQUITY",
"region": "US",
"regularMarketChange": 8.62999,
"regularMarketChangePercent": 4.2583585,
"regularMarketDayHigh": 214.8399,
"regularMarketDayLow": 206.7,
"regularMarketDayRange": "206.7 - 214.8399",
"regularMarketOpen": 207.6,
"regularMarketPreviousClose": 202.66,
"regularMarketPrice": 211.29,
"regularMarketTime": 1599681601,
"regularMarketVolume": 43764495,
"sharesOutstanding": 7567649792,
"shortName": "Microsoft Corporation",
"sourceInterval": 15,
"symbol": "MSFT",
"tradeable": false,
"trailingAnnualDividendRate": 2.04,
"trailingAnnualDividendYield": 0.01006612,
"trailingPE": 36.68229,
"triggerable": true,
"twoHundredDayAverage": 186.7529,
"twoHundredDayAverageChange": 24.537094,
"twoHundredDayAverageChangePercent": 0.13138802
}
]
}
}
どのように構造体を定義すればよいか
方法１
シンプルにJSON-TO-GOで生成された定義のまま
type Quote struct {
QuoteResponse struct {
Error interface{} `json:"error"`
Result []struct {
Ask float64 `json:"ask"`
AskSize int `json:"askSize"`
AverageDailyVolume10Day int `json:"averageDailyVolume10Day"`
AverageDailyVolume3Month int `json:"averageDailyVolume3Month"`
Bid float64 `json:"bid"`
BidSize int `json:"bidSize"`
BookValue float64 `json:"bookValue"`
Currency string `json:"currency"`
DisplayName string `json:"displayName"`
DividendDate int `json:"dividendDate"`
EarningsTimestamp int `json:"earningsTimestamp"`
EarningsTimestampEnd int `json:"earningsTimestampEnd"`
EarningsTimestampStart int `json:"earningsTimestampStart"`
EpsCurrentYear float64 `json:"epsCurrentYear"`
EpsForward float64 `json:"epsForward"`
EpsTrailingTwelveMonths float64 `json:"epsTrailingTwelveMonths"`
EsgPopulated bool `json:"esgPopulated"`
Exchange string `json:"exchange"`
ExchangeDataDelayedBy int `json:"exchangeDataDelayedBy"`
ExchangeTimezoneName string `json:"exchangeTimezoneName"`
ExchangeTimezoneShortName string `json:"exchangeTimezoneShortName"`
FiftyDayAverage float64 `json:"fiftyDayAverage"`
FiftyDayAverageChange float64 `json:"fiftyDayAverageChange"`
FiftyDayAverageChangePercent float64 `json:"fiftyDayAverageChangePercent"`
FiftyTwoWeekHigh float64 `json:"fiftyTwoWeekHigh"`
FiftyTwoWeekHighChange float64 `json:"fiftyTwoWeekHighChange"`
FiftyTwoWeekHighChangePercent float64 `json:"fiftyTwoWeekHighChangePercent"`
FiftyTwoWeekLow float64 `json:"fiftyTwoWeekLow"`
FiftyTwoWeekLowChange float64 `json:"fiftyTwoWeekLowChange"`
FiftyTwoWeekLowChangePercent float64 `json:"fiftyTwoWeekLowChangePercent"`
FiftyTwoWeekRange string `json:"fiftyTwoWeekRange"`
FinancialCurrency string `json:"financialCurrency"`
FirstTradeDateMilliseconds int64 `json:"firstTradeDateMilliseconds"`
ForwardPE float64 `json:"forwardPE"`
FullExchangeName string `json:"fullExchangeName"`
GmtOffSetMilliseconds int `json:"gmtOffSetMilliseconds"`
Language string `json:"language"`
LongName string `json:"longName"`
Market string `json:"market"`
MarketCap int64 `json:"marketCap"`
MarketState string `json:"marketState"`
MessageBoardID string `json:"messageBoardId"`
PostMarketChange float64 `json:"postMarketChange"`
PostMarketChangePercent float64 `json:"postMarketChangePercent"`
PostMarketPrice float64 `json:"postMarketPrice"`
PostMarketTime int `json:"postMarketTime"`
PriceEpsCurrentYear float64 `json:"priceEpsCurrentYear"`
PriceHint int `json:"priceHint"`
PriceToBook float64 `json:"priceToBook"`
QuoteSourceName string `json:"quoteSourceName"`
QuoteType string `json:"quoteType"`
Region string `json:"region"`
RegularMarketChange float64 `json:"regularMarketChange"`
RegularMarketChangePercent float64 `json:"regularMarketChangePercent"`
RegularMarketDayHigh float64 `json:"regularMarketDayHigh"`
RegularMarketDayLow float64 `json:"regularMarketDayLow"`
RegularMarketDayRange string `json:"regularMarketDayRange"`
RegularMarketOpen float64 `json:"regularMarketOpen"`
RegularMarketPreviousClose float64 `json:"regularMarketPreviousClose"`
RegularMarketPrice float64 `json:"regularMarketPrice"`
RegularMarketTime int `json:"regularMarketTime"`
RegularMarketVolume int `json:"regularMarketVolume"`
SharesOutstanding int64 `json:"sharesOutstanding"`
ShortName string `json:"shortName"`
SourceInterval int `json:"sourceInterval"`
Symbol string `json:"symbol"`
Tradeable bool `json:"tradeable"`
TrailingAnnualDividendRate float64 `json:"trailingAnnualDividendRate"`
TrailingAnnualDividendYield float64 `json:"trailingAnnualDividendYield"`
TrailingPE float64 `json:"trailingPE"`
Triggerable bool `json:"triggerable"`
TwoHundredDayAverage float64 `json:"twoHundredDayAverage"`
TwoHundredDayAverageChange float64 `json:"twoHundredDayAverageChange"`
TwoHundredDayAverageChangePercent float64 `json:"twoHundredDayAverageChangePercent"`
} `json:"result"`
} `json:"quoteResponse"`
}
方法２
階層ごとに構造体を定義する。
type Quote struct {
QuoteResponse QuoteResponse `json:"quoteResponse"`
}
type QuoteResponse struct {
Error interface{} `json:"error"`
Result []Result `json:"result"`
}
type Result struct {
Ask float64 `json:"ask"`
AskSize int `json:"askSize"`
AverageDailyVolume10Day int `json:"averageDailyVolume10Day"`
AverageDailyVolume3Month int `json:"averageDailyVolume3Month"`
Bid float64 `json:"bid"`
BidSize int `json:"bidSize"`
BookValue float64 `json:"bookValue"`
Currency string `json:"currency"`
DisplayName string `json:"displayName"`
DividendDate int `json:"dividendDate"`
EarningsTimestamp int `json:"earningsTimestamp"`
EarningsTimestampEnd int `json:"earningsTimestampEnd"`
EarningsTimestampStart int `json:"earningsTimestampStart"`
EpsCurrentYear float64 `json:"epsCurrentYear"`
EpsForward float64 `json:"epsForward"`
EpsTrailingTwelveMonths float64 `json:"epsTrailingTwelveMonths"`
EsgPopulated bool `json:"esgPopulated"`
Exchange string `json:"exchange"`
ExchangeDataDelayedBy int `json:"exchangeDataDelayedBy"`
ExchangeTimezoneName string `json:"exchangeTimezoneName"`
ExchangeTimezoneShortName string `json:"exchangeTimezoneShortName"`
FiftyDayAverage float64 `json:"fiftyDayAverage"`
FiftyDayAverageChange float64 `json:"fiftyDayAverageChange"`
FiftyDayAverageChangePercent float64 `json:"fiftyDayAverageChangePercent"`
FiftyTwoWeekHigh float64 `json:"fiftyTwoWeekHigh"`
FiftyTwoWeekHighChange float64 `json:"fiftyTwoWeekHighChange"`
FiftyTwoWeekHighChangePercent float64 `json:"fiftyTwoWeekHighChangePercent"`
FiftyTwoWeekLow float64 `json:"fiftyTwoWeekLow"`
FiftyTwoWeekLowChange float64 `json:"fiftyTwoWeekLowChange"`
FiftyTwoWeekLowChangePercent float64 `json:"fiftyTwoWeekLowChangePercent"`
FiftyTwoWeekRange string `json:"fiftyTwoWeekRange"`
FinancialCurrency string `json:"financialCurrency"`
FirstTradeDateMilliseconds int64 `json:"firstTradeDateMilliseconds"`
ForwardPE float64 `json:"forwardPE"`
FullExchangeName string `json:"fullExchangeName"`
GmtOffSetMilliseconds int `json:"gmtOffSetMilliseconds"`
Language string `json:"language"`
LongName string `json:"longName"`
Market string `json:"market"`
MarketCap int64 `json:"marketCap"`
MarketState string `json:"marketState"`
MessageBoardID string `json:"messageBoardId"`
PostMarketChange float64 `json:"postMarketChange"`
PostMarketChangePercent float64 `json:"postMarketChangePercent"`
PostMarketPrice float64 `json:"postMarketPrice"`
PostMarketTime int `json:"postMarketTime"`
PriceEpsCurrentYear float64 `json:"priceEpsCurrentYear"`
PriceHint int `json:"priceHint"`
PriceToBook float64 `json:"priceToBook"`
QuoteSourceName string `json:"quoteSourceName"`
QuoteType string `json:"quoteType"`
Region string `json:"region"`
RegularMarketChange float64 `json:"regularMarketChange"`
RegularMarketChangePercent float64 `json:"regularMarketChangePercent"`
RegularMarketDayHigh float64 `json:"regularMarketDayHigh"`
RegularMarketDayLow float64 `json:"regularMarketDayLow"`
RegularMarketDayRange string `json:"regularMarketDayRange"`
RegularMarketOpen float64 `json:"regularMarketOpen"`
RegularMarketPreviousClose float64 `json:"regularMarketPreviousClose"`
RegularMarketPrice float64 `json:"regularMarketPrice"`
RegularMarketTime int `json:"regularMarketTime"`
RegularMarketVolume int `json:"regularMarketVolume"`
SharesOutstanding int64 `json:"sharesOutstanding"`
ShortName string `json:"shortName"`
SourceInterval int `json:"sourceInterval"`
Symbol string `json:"symbol"`
Tradeable bool `json:"tradeable"`
TrailingAnnualDividendRate float64 `json:"trailingAnnualDividendRate"`
TrailingAnnualDividendYield float64 `json:"trailingAnnualDividendYield"`
TrailingPE float64 `json:"trailingPE"`
Triggerable bool `json:"triggerable"`
TwoHundredDayAverage float64 `json:"twoHundredDayAverage"`
TwoHundredDayAverageChange float64 `json:"twoHundredDayAverageChange"`
TwoHundredDayAverageChangePercent float64 `json:"twoHundredDayAverageChangePercent"`
}
値を出力してみる
実際に値を取り出す際の実行例を示します。
値の取り出し方については方法１、方法２共に同じです。
試してみるときはあらかじめ「JSONのレスポンス例」で示したデータをmain.goと同じ階層に「test.json」として保存しておいてください。
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"log"
"os"
)
type Quote struct {
QuoteResponse struct {
Error interface{} `json:"error"`
Result []struct {
Ask float64 `json:"ask"`
AskSize int `json:"askSize"`
AverageDailyVolume10Day int `json:"averageDailyVolume10Day"`
AverageDailyVolume3Month int `json:"averageDailyVolume3Month"`
Bid float64 `json:"bid"`
BidSize int `json:"bidSize"`
BookValue float64 `json:"bookValue"`
Currency string `json:"currency"`
DisplayName string `json:"displayName"`
DividendDate int `json:"dividendDate"`
EarningsTimestamp int `json:"earningsTimestamp"`
EarningsTimestampEnd int `json:"earningsTimestampEnd"`
EarningsTimestampStart int `json:"earningsTimestampStart"`
EpsCurrentYear float64 `json:"epsCurrentYear"`
EpsForward float64 `json:"epsForward"`
EpsTrailingTwelveMonths float64 `json:"epsTrailingTwelveMonths"`
EsgPopulated bool `json:"esgPopulated"`
Exchange string `json:"exchange"`
ExchangeDataDelayedBy int `json:"exchangeDataDelayedBy"`
ExchangeTimezoneName string `json:"exchangeTimezoneName"`
ExchangeTimezoneShortName string `json:"exchangeTimezoneShortName"`
FiftyDayAverage float64 `json:"fiftyDayAverage"`
FiftyDayAverageChange float64 `json:"fiftyDayAverageChange"`
FiftyDayAverageChangePercent float64 `json:"fiftyDayAverageChangePercent"`
FiftyTwoWeekHigh float64 `json:"fiftyTwoWeekHigh"`
FiftyTwoWeekHighChange float64 `json:"fiftyTwoWeekHighChange"`
FiftyTwoWeekHighChangePercent float64 `json:"fiftyTwoWeekHighChangePercent"`
FiftyTwoWeekLow float64 `json:"fiftyTwoWeekLow"`
FiftyTwoWeekLowChange float64 `json:"fiftyTwoWeekLowChange"`
FiftyTwoWeekLowChangePercent float64 `json:"fiftyTwoWeekLowChangePercent"`
FiftyTwoWeekRange string `json:"fiftyTwoWeekRange"`
FinancialCurrency string `json:"financialCurrency"`
FirstTradeDateMilliseconds int64 `json:"firstTradeDateMilliseconds"`
ForwardPE float64 `json:"forwardPE"`
FullExchangeName string `json:"fullExchangeName"`
GmtOffSetMilliseconds int `json:"gmtOffSetMilliseconds"`
Language string `json:"language"`
LongName string `json:"longName"`
Market string `json:"market"`
MarketCap int64 `json:"marketCap"`
MarketState string `json:"marketState"`
MessageBoardID string `json:"messageBoardId"`
PostMarketChange float64 `json:"postMarketChange"`
PostMarketChangePercent float64 `json:"postMarketChangePercent"`
PostMarketPrice float64 `json:"postMarketPrice"`
PostMarketTime int `json:"postMarketTime"`
PriceEpsCurrentYear float64 `json:"priceEpsCurrentYear"`
PriceHint int `json:"priceHint"`
PriceToBook float64 `json:"priceToBook"`
QuoteSourceName string `json:"quoteSourceName"`
QuoteType string `json:"quoteType"`
Region string `json:"region"`
RegularMarketChange float64 `json:"regularMarketChange"`
RegularMarketChangePercent float64 `json:"regularMarketChangePercent"`
RegularMarketDayHigh float64 `json:"regularMarketDayHigh"`
RegularMarketDayLow float64 `json:"regularMarketDayLow"`
RegularMarketDayRange string `json:"regularMarketDayRange"`
RegularMarketOpen float64 `json:"regularMarketOpen"`
RegularMarketPreviousClose float64 `json:"regularMarketPreviousClose"`
RegularMarketPrice float64 `json:"regularMarketPrice"`
RegularMarketTime int `json:"regularMarketTime"`
RegularMarketVolume int `json:"regularMarketVolume"`
SharesOutstanding int64 `json:"sharesOutstanding"`
ShortName string `json:"shortName"`
SourceInterval int `json:"sourceInterval"`
Symbol string `json:"symbol"`
Tradeable bool `json:"tradeable"`
TrailingAnnualDividendRate float64 `json:"trailingAnnualDividendRate"`
TrailingAnnualDividendYield float64 `json:"trailingAnnualDividendYield"`
TrailingPE float64 `json:"trailingPE"`
Triggerable bool `json:"triggerable"`
TwoHundredDayAverage float64 `json:"twoHundredDayAverage"`
TwoHundredDayAverageChange float64 `json:"twoHundredDayAverageChange"`
TwoHundredDayAverageChangePercent float64 `json:"twoHundredDayAverageChangePercent"`
} `json:"result"`
} `json:"quoteResponse"`
}
func main() {
file, err := ioutil.ReadFile("./test.json")
if err != nil {
log.Println("ReadError: ", err)
os.Exit(1)
}
var quote Quote
json.Unmarshal(file, "e)
fmt.Println("quoteの値すべてを出力")
fmt.Println(quote)
fmt.Println("Resultの1番目の配列のAskのみ取り出す")
fmt.Println(quote.QuoteResponse.Result[0].Ask)
}
実行結果
quoteの値すべてを出力
{{<nil> [{117.27 8 233119800 170533131 117.25 22 4.218 USD Apple 1597276800 1596126600 1604318400 1603882740 3.23 3.86 3.296 false NMS 0 America/New_York EDT 112.823425 4.4965744 0.03985497 137.98 -20.659996 -0.14973181 53.1525 64.167496 1.2072338 53.1525 - 137.98 USD 345479400000 30.393784 NasdaqGS -14400000 en-US Apple Inc. us_market 2006465249280 POST finmb_24937 -0.25 -0.2130924 117.07 1599686591 36.32198 2 27.81413 Nasdaq Real Time Price EQUITY US 4.5 3.9886546 119.14 115.26 115.26 - 119.14 117.26 112.82 117.32 1599681602 168404235 17102499840 Apple Inc. 15 AAPL false 0.782 0.0069313953 35.59466 true 85.99835 31.321648 0.3642122} {211.63 9 43250000 35562815 211.25 9 15.626 USD Microsoft 1599696000 1595434164 1603742400 1603310400 6.46 7.34 5.76 false NMS 0 America/New_York EDT 212.50658 -1.2165833 -0.0057249204 232.86 -21.570007 -0.092630796 132.52 78.76999 0.59440076 132.52 - 232.86 USD 511108200000 28.786102 NasdaqGS -14400000 en-US Microsoft Corporation us_market 1598968692736 POST finmb_21835 -61.5672 -29.13872 149.7228 1599686588 32.707428 2 13.521694 Nasdaq Real Time Price EQUITY US 8.62999 4.2583585 214.8399 206.7 206.7 - 214.8399 207.6 202.66 211.29 1599681601 43764495 7567649792 Microsoft Corporation 15 MSFT false 2.04 0.01006612 36.68229 true 186.7529 24.537094 0.13138802}]}}
Resultの1番目の配列のAskのみ取り出す
117.27
まとめ
JSON -TO-GOのありがたみを感じました。なんて楽なんでしょう。
理解してしまえばなんてことはないので今後はつまずかずにできそうです。