Date as xlim in R - r

Question

I was trying to draw some lines in the same plot. The x factor is determined by a date and the y factor by a number. I initially load the data, store it in a list and save the min and max values for the date:
stocks <- list()
stocks.min <- 0
stocks.max <- 0
stocks.min.date <- NULL
stocks.max.date <- NULL
for (name in names(files))
{
stocks[[name]] <- read.csv(files[[name]], sep=";")
# Convert to date in R
stocks[[name]]$Date <- as.Date(stocks[[name]]$Date, "%d/%m/%Y")
# Sets max value for ylim in the plotting
if (stocks.max < max(stocks[[name]]$Close))
{
stocks.max <- max(stocks[[name]]$Close)
}
# Sets the date value for the xlim in the plot
if (is.null(stocks.min.date) || min(stocks[[name]]$Date) < stocks.min.date)
{
stocks.min.date <- min(stocks[[name]]$Date)
}
if (is.null(stocks.max.date) || max(stocks[[name]]$Date) > stocks.max.date)
{
stocks.max.date <- max(stocks[[name]]$Date)
}
}
After that I create an empty plot using the values from above:
plot(0, xlab="Time", ylab="Closing Prices", main="Stock Values",
xlim=c(stocks.min.date, stocks.max.date), ylim=c(stocks.min, stocks.max))
And then I add the lines with the data:
for (name in names(stocks))
{
lines(x=stocks[[name]]$Date, y=stocks[[name]]$Close, col=colors[[name]], type="l",
lwd=2)
}
When the graph is plotted, the data is correctly displayed, but it shows the date as numbers instead of dates in the x axis as seen in the image below:
How can I correct this issue?

Answer 1

I would strongly suggest using a normalized series to plot the stocks data you have. quantmod helps a lot here. It solves two purposes -
Get the x-axis labels as dates.
Normalize series so that you can view any number of series without worrying about the orders of their absolute values (~67 for INR, ~1120 for KRW, so on...)
This is what I generally use for my purposes.
library(quantmod)
tickers <- c('GOOG', 'MSFT', 'AAPL', 'AMZN')
getSymbols(tickers, src = 'yahoo', from = '2015-01-01')
normalise <- function(x) x/as.numeric(x)[1] - 1
chart_theme <- chart_theme()
chart_theme$col$line.col <- "red"
chart_Series(normalise(Cl(GOOG)), theme = chart_theme)
add_TA(normalise(Cl(MSFT)), on = 1, col = "black", lty = 1)
add_TA(normalise(Cl(AMZN)), on = 1, col = "blue", lty =1)
add_TA(normalise(Cl(AAPL)), on = 1, col = "darkgreen", lty =2)
Hope this helps.