如何查看quantmod包中的所有可用数据系列？

如何显示所有报价/数据系列的列表,例如来自Yahoo的getSymbols？

我不知道怎么回事.TTR包有一个函数(stockSymbols)来从纽约证券交易所,美国证券交易所和纳斯达克下载所有当前符号.它试图将它们置于可接受的雅虎格式中,但不能保证它检索的6,000多个符号在雅虎上有数据.我不知道该为其他交易所做些什么......

> library(TTR)
> x <- stockSymbols()
Fetching AMEX symbols...
Fetching NASDAQ symbols...
Fetching NYSE symbols...
> str(x)
'data.frame':   6473 obs. of  8 variables:
 $ Symbol   : chr  "ADK" "ADK-WT" "AFP" "AIM" ...
 $ Name     : chr  "Adcare Health Systems Inc" "Adcare Health Systems Inc" "United Capital Corporation" "Aerosonic Corporation" ...
 $ LastSale : num  4.12 2.1 30 2.73 2.7 ...
 $ MarketCap: num  3.28e+07 0.00 2.68e+08 1.02e+07 9.29e+07 ...
 $ IPOyear  : num  NA NA 1973 NA NA ...
 $ Sector   : chr  "Health Care" "n/a" "Capital Goods" "Capital Goods" ...
 $ Industry : chr  "Hospital/Nursing Management" "n/a" "Metal Fabrications" "Industrial Machinery/Components" ...
 $ Exchange : chr  "AMEX" "AMEX" "AMEX" "AMEX" ...