[R] embedding expression into title in R plot

[Evan Cooch]

David --

On 1/11/2016 1:01 PM, David Winsemius wrote:
>
>> On Jan 11, 2016, at 7:59 AM, Evan Cooch <evan.cooch at gmail.com> wrote:
>>
>> Suppose I've specified that the xlab for a plot is
>>
>> expression(bold(species~(italic(N1))))
>>
>> In other words, I want the axis label to be bold, italic 'species (N1)'
>>
>> Now, I want the title for the plot to be have this label embedded in the
>> title.
>>
>> Say, 'This is the plot for Species (N1)'.
>>
>> For a variety of reasons, I've set this up so that the xlab is a global
>> parameter (basically, because the labels are set in a function which
>> when called, generates various plots):
>>
>> x_label <<- expression(bold(species~(italic(N1))))
>
>>
>> So, in the title, I've tried
>>
>>   title(main=paste("This is the plot for ",x_label,"nullcline", sep=" "));
>>
>> but what this does is generate something like
>>
>> 'This is the plot for bold(species~(italic(N1)))'
>>
>> In other words, it pastes the text of the expression into the title, but
>> not what the expression 'evaluates' to.
>>
>> Is there any way around this?
>
> You instead need the `bquote` function. The `paste` function will only confuse things. In this particular instance it is embedding the literal as.character result of 'x_label'-value in a character object rather than in an expression-object. Since you have not offered a full example it remains unclear whether you want the words: "species" or "N1" rather than the values of those names.
>

Thanks. I had wondered if bquote was the solution, but wasn't sure. Have 
followed your suggestion, but for the moment, am having problems getting 
it to work. I haven't figured out how to get bquote to actually evaulate 
the expression.

>
>>
>> Thanks in advance...
>>
>>
>> 	[[alternative HTML version deleted]]
>
> This is a plain text mailing list.
>>

Indeed -- forgot to flip the switch on my email client, which defaults 
to sending both plain text and HTML email.

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>
> David Winsemius
> Alameda, CA, USA
>
>