[R] Subscript in axis label

[Peter Dalgaard]

Tobias Verbeke wrote:
> pm509 at york.ac.uk wrote:
>   
>> Dear R help list members,
>>
>> I am experiencing difficulty in trying to generate a subscript '2' in an 
>> axis label. Although I can get the '2' into a subscript using expression(), 
>> R then forces me to leave at least one space between the '2' and the 
>> following character. My label is supposed to read 'N2O concentration 
>> (ppm)', and the space between the '2' and the 'O' makes it look rather 
>> inelegant! My code is the following (the comments in it are there to stop 
>> me forgetting what I have done, I am new to R):
>>
>> postscript(file="/Users/patrickmartin/Documents/York Innova 
>> Precision/N2Oinnova.eps", horizontal=FALSE, onefile=FALSE, height=4, 
>> width=5, pointsize=10)
>>     
>>> plot(n2o, lty=0, las=1, xlab="Time", ylab=expression(N[2]~"O 
>>> concentration (ppm)")) points(n2o, pch=16) # suppresses line but adds 
>>> points dev.off() # turns postscript device off again
>>>       
>
> Is this better
>
> plot(1:10, ylab = expression(paste(N[2],"O concentration (ppm)",
>                               sep = "")))
>   

Or,

plot(1:10, ylab = expression(N[2]*O~"concentration (ppm)"))

(because of the "~", you can even do away with "expression()", but I 
think that would be overly sneaky.)