交易符号和市场ID

市场ID用于在REST请求-响应过程中引用交易所内的交易对。每个交易所都有不同的市场ID集，因此不可以跨交易所使用市场ID。例如，BTC/USD 交易对在不同的交易所中可能有不同的ID：btcusd、 BTCUSD、XBTUSD、btc/usd、 42 (数字ID)、 BTC/USD、 Btc/Usd、 tBTCUSD、 XXBTZUSD等。你不需要记住或使用市场ID，他们的作用是在交易所模型实现的内部用于HTTP的请求 -响应目的。

CCXT库将不通用的市场ID抽象为标准化的交易符号。交易符号不同于市场ID。每个市场都采用一个对应的符号来引用，交易符号可以跨交易所使用，这使得交易符号更适用于跨交易所套利等其他很多应用。

交易符号通常是描述一对交易货币的大写字符串常量，以斜杠间隔两个货币代码。货币代码是3~4位大写字母，例如 BTC, ETH, USD, GBP, CNY, LTC, JPY, DOGE, RUB, ZEC, XRP, XMR, 等等。有些交易所也有长一些的富有异国风情的货币名称。在斜杠之前的货币被称为基础货币，之后的被称为报价货币。下面是一些符号的示例： BTC/USD, DOGE/LTC, ETH/EUR, DASH/XRP, BTC/CNY, ZEC/XMR, ETH/JPY。

有时用户可能会注意到像'XBTM18' 或'.XRPUSDM20180101' 或r "exotic/rare symbols" 之类的交易符号。交易符号并不是一定要有斜杠或者包含货币对的代码。符号字符串完全取决于市场类型（它是一个现货市场、期货市场、暗池市场或过期市场等等）。 CCXT不鼓励你解析交易符号字符串，你不应该依赖于交易符号的格式，CCXT推荐你使用市场属性来达成你的应用需求。

市场结构使用符号和ID为键。交易所基类也有内置的方法可以按符号访问市场对象。大多数 API方法需要传入交易符号作为第一个参数。当查询当前价格或委托下单时，也常常需要你指定一个交易符号。

大多数时候，CCXT用户都是与市场交易符号打交道。如果你访问字典中不存在的键，就会收获一个异常。

JavaScript示例代码：

(async () => {

    console.log (await exchange.loadMarkets ())

    let btcusd1 = exchange.markets['BTC/USD']     // get market structure by symbol
    let btcusd2 = exchange.market ('BTC/USD')     // same result in a slightly different way

    let btcusdId = exchange.marketId ('BTC/USD')  // get market id by symbol

    let symbols = exchange.symbols                // get an array of symbols
    let symbols2 = Object.keys (exchange.markets) // same as previous line

    console.log (exchange.id, symbols)            // print all symbols

    let currencies = exchange.currencies          // a list of currencies

    let bitfinex = new ccxt.bitfinex ()
    await bitfinex.loadMarkets ()

    bitfinex.markets['BTC/USD']                   // symbol → market (get market by symbol)
    bitfinex.markets_by_id['XRPBTC']              // id → market (get market by id)

    bitfinex.markets['BTC/USD']['id']             // symbol → id (get id by symbol)
    bitfinex.markets_by_id['XRPBTC']['symbol']    // id → symbol (get symbol by id)

})

Python示例代码：

print (exchange.load_markets ())

etheur1 = exchange.markets['ETH/EUR']      # get market structure by symbol
etheur2 = exchange.market ('ETH/EUR')      # same result in a slightly different way

etheurId = exchange.market_id ('BTC/USD')  # get market id by symbol

symbols = exchange.symbols                 # get a list of symbols
symbols2 = list (exchange.markets.keys ()) # same as previous line

print (exchange.id, symbols)               # print all symbols

currencies = exchange.currencies           # a list of currencies

kraken = ccxt.kraken ()
kraken.load_markets ()

kraken.markets['BTC/USD']                  # symbol → market (get market by symbol)
kraken.markets_by_id['XXRPZUSD']           # id → market (get market by id)

kraken.markets['BTC/USD']['id']            # symbol → id (get id by symbol)
kraken.markets_by_id['XXRPZUSD']['symbol'] # id → symbol (get symbol by id)

PHP示例代码：

$var_dump ($exchange->load_markets ());

$dashcny1 = $exchange->markets['DASH/CNY'];     // get market structure by symbol
$dashcny2 = $exchange->market ('DASH/CNY');     // same result in a slightly different way

$dashcnyId = $exchange->market_id ('DASH/CNY'); // get market id by symbol

$symbols = $exchange->symbols;                  // get an array of symbols
$symbols2 = array_keys ($exchange->markets);    // same as previous line

var_dump ($exchange->id, $symbols);             // print all symbols

$currencies = $exchange->currencies;            // a list of currencies

$okcoinusd = '\\ccxt\\okcoinusd';
$okcoinusd = new $okcoinusd ();

$okcoinusd->load_markets ();

$okcoinusd->markets['BTC/USD'];                 // symbol → market (get market by symbol)
$okcoinusd->markets_by_id['btc_usd'];           // id → market (get market by id)

$okcoinusd->markets['BTC/USD']['id'];           // symbol → id (get id by symbol)
$okcoinusd->markets_by_id['btc_usd']['symbol']; // id → symbol (get symbol by id)

CCXT中文开发手册

交易符号和市场ID