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

Please review the contributing guide before submitting your pull request. Please pay special attention to the pull request and commit message sections. Thanks for your contribution and interest in the project!

[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]

At minimum, the hasArg() bug needs to be fixed. We also should not force the plot to be rendered. That's what all the expression logic and chart.lines() accomplish.

[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.