Add ylab to plot.xts

[jaymon0703]

Few things worth mentioning:

1. Tried to do this in chart.lines() but ylab was not passing through
2. Need a solution for when multi.panel is not NULL, perhaps a character vector of ylab strings?
3. Needed the plot printed before i could add title() hence cs becomes plot(cs)

Simple test is add ylab argument to plot.xts()

See #333

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[jaymon0703]

I should mention i did try sub and xlab args, but they overlap the x-axis labels so would not work without some extra effort which im not sure is warranted.

[joshuaulrich]

This seems to work for me. Can you try it and see if it does what you expect?

diff --git a/R/plot.R b/R/plot.R
index 01474a3..11b6fcc 100644
--- a/R/plot.R
+++ b/R/plot.R
@@ -286,6 +286,7 @@ plot.xts <- function(x,
   cs$Env$column_names <- colnames(x)
   cs$Env$nobs <- NROW(cs$Env$xdata)
   cs$Env$main <- main
+  cs$Env$ylab <- if (hasArg("ylab")) eval.parent(plot.call$ylab) else ""

   # Set xlim using the raw returns data passed into function
   # xlim can be based on observations or time
@@ -411,6 +412,10 @@ plot.xts <- function(x,
                              col=theme$labels, srt=theme$srt, offset=1, pos=4,
                              cex=theme$cex.axis, xpd=TRUE)))
   }
+
+  # ylab
+  exp <- c(exp, expression(title(ylab = ylab[1], mgp = c(1, 1, 0))))
+
   cs$add(exp, env=cs$Env, expr=TRUE)

   # add main series

[jaymon0703]

Thanks Josh. Is there a way for me to pull your changes, or must i add them manually?

[joshuaulrich]

I can push them to your branch if they look good to you.

[jaymon0703]

I can push them to your branch if they look good to you.

Thanks Josh, it works. Feel free to push.

[joshuaulrich]

I just noticed your comment about how to handle when multi.panel != NULL. Did you try that with my change? Do you think we should try adding that now, or wait to handle it in a separate issue/PR? My slight preference would be to merge this and deal with the multi.panel case later.

[jaymon0703]

Later is fine. I have pulled your changes, thanks. It seems the PR is updated with your changes. Is there anything left for me to do on the PR?

[joshuaulrich]

Nothing more for you to do. I just needed to merge. Thanks for this suggestion and feedback!

[jaymon0703]

Thank you Josh.

[jaymon0703]

The idea came from some algoTCA charts we plot with xts in blotter. Now we can show the metric for the y-axis. Thanks again.