R 中時間序列圖上的圖例

Question

如何在下面的 plot 中添加圖例？ 我查看了互聯網上的各種文章，但似乎沒有一篇能讓我有所收獲。 將不勝感激任何幫助。

library(quantmod)
library(PerformanceAnalytics)
library(imputeTS)
library(PortfolioAnalytics)

tickers <- c("FB", "AAPL", "AMZN", "NFLX")
weights <- c(.25, .25, .25, .25)

portfolioPrices <- NULL
for (Ticker in tickers)
  portfolioPrices <- cbind(portfolioPrices,
                           getSymbols.yahoo(Ticker, from="2016-01-01", periodicity = "daily", auto.assign=FALSE)[,4])

plot(portfolioPrices, legend = tickers)

PS：對於模組 - 請不要關閉我的問題，我已經查看了網站上的其他類似帖子，但它們沒有幫助我。

Answer 1

如果您將portfolioPrices 轉換為dataframe 然后分別添加每一行，您可以添加一個圖例。

以下代碼不會創建最好看的情節/圖例，但您可以通過使用圖例/情節 arguments 來改進它。

此外，可以使用循環而不是硬編碼來添加行。

library(quantmod)
library(PerformanceAnalytics)
library(imputeTS)
library(PortfolioAnalytics)

tickers <- c("FB", "AAPL", "AMZN", "NFLX")
weights <- c(.25, .25, .25, .25)

portfolioPrices <- NULL
for (Ticker in tickers)
  portfolioPrices <- cbind(
    portfolioPrices,
    getSymbols.yahoo(
      Ticker,
      from = "2016-01-01",
      periodicity = "daily",
      auto.assign = FALSE
    )[, 4]
  )
portfolioPrices <- data.frame(portfolioPrices)


plot(
  x = as.Date(rownames(portfolioPrices)),
  portfolioPrices$FB.Close,
  col = "black",
  type = "l",
  ylim = c(min(portfolioPrices), max(portfolioPrices)),
  main = "Stocks",
  xlab = "Date",
  ylab = "Price"
)
lines(x = as.Date(rownames(portfolioPrices)),
      portfolioPrices$AAPL.Close,
      col = "blue")
lines(x = as.Date(rownames(portfolioPrices)),
      portfolioPrices$AMZN.Close,
      col = "green")
lines(x = as.Date(rownames(portfolioPrices)),
      portfolioPrices$NFLX.Close,
      col = "red")

legend(
  "topleft",
  legend = tickers,
  col = c("black", "blue", "green", "red"),
  cex = 0.5,
  lwd = 2
)