R: MIssing legend when using scale_fill_manual

When configuring ggplot using scale_fill_manual in R, sometimes the legend might not be displayed. This happens when we specify 'breaks' property within the scale_fill_manual command, and the values we supply don't correspond to the factor levels we use in fill.

For instance, assume we have a data frame with columns 'X', 'Y', and 'Type', where 'Type' contains values 'A' and 'B'. In the below ggplot/ggplot2 command, breaks argument cannot contain a list of strings which do not map to factor levels in column 'Type':

ggplot2(data=df, aes(x=X, y=Y, fill=Type)) + 
scale_fill_manual(values=c("black","red", name="Type", breaks=c("A","B"), labels=c("Type-A","Type-B"))

Instead, we need to specify the breaks as:

ggplot2(data=df, aes(x=X, y=Y, fill=Type)) + 
scale_fill_manual(values=c("black","red", name="Type", breaks=levels(factor(df$Type)), labels=c("Type-A","Type-B"))

Or as below, if we are sure of the factor ordering:

ggplot2(data=df, aes(x=X, y=Y, fill=Type)) + 
scale_fill_manual(values=c("black","red", name="Type", labels=c("Type-A","Type-B"))

References:
1. http://stackoverflow.com/questions/14546858/missing-legend-when-combining-scale-fill-manual-and-scale-x-discrete-in-bar-char

Latex 'pdfpagelabels' turned off when using Hyperref

I received the following error when using ACM's sig-alternate.cls style file and using the PDFLatex command.

Error:
Package hyperref Warning: Option `pdfpagelabels' is turned off
hyperref because \thepage is undefined.

That seems to be caused by an update of the hyperref package. The workaround is to switch this option off.
Instead of using:

\usepackage{hyperref}

Use:

\PassOptionsToPackage{pdfpagelabels=true}{hyperref}

References:
1. http://www.latex-community.org/forum/viewtopic.php?f=5&t=162

Vertical xtick Labels in Matlab graphs

This was taken from the mailing list entry available at: https://mailman.cae.wisc.edu/pipermail/help-octave/2009-July/036066.html
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here is a script that illustrates how to rotate the xtick label and put them vertically.

clear

## init demo plot

clf

plot(1:4);

xtick=[1 2 3 4];

set(gca,'xtick',xtick);

xticklabel=["a";"b";"c";"d"];

set(gca,'xticklabel',xticklabel);



## get position of current xtick labels

h = get(gca,'xlabel');

xlabelstring = get(h,'string');

xlabelposition = get(h,'position');



## construct position of new xtick labels

yposition = xlabelposition(2);

yposition = repmat(yposition,length(xtick),1);



## disable current xtick labels

set(gca,'xtick',[]);



## set up new xtick labels and rotate

hnew = text(xtick, yposition, xticklabel);

set(hnew,'rotation',90,'horizontalalignment','right');