Use of plot and curve in rpy2
<p>In R, I can run plot and curve to get the relationship between a predicted probability and the predictor variable by just running:</p>

<pre><code>plot(outcome~survrate, data = d, ylab = "P(outcome = 1 |
survrate)", xlab = "SURVRATE: Probability of Survival after 5
Years", xaxp = c(0, 95, 19))

curve(transform(coef(mod1)[1] + coef(mod1)[2]*x), add = TRUE)
</code></pre>

<p>Where transform is a custom R function.</p>

<p>I am trying to do the same thing in rpy2, and so far have the following:</p>

<pre><code>rplot = ro.r('plot')
formula = Formula('outcome~survrate')
formula.getenvironment()['outcome'] = r_analytical_set.rx2('outcome')
formula.getenvironment()['survrate'] = r_analytical_set.rx2('survrate')
ro.r.plot(formula, data=r_analytical_set, ylab = 'P(outcome =  1 | pass)', xlab = 'SURVRATE: Probability of Survival after 5
Years', xaxp = ro.r.c(0, 95, 19))

# read in R function from file
with open('/Users/gregsilverman//development/python/rest_api/rest_api/utils.r', 'r') as f:
    string = f.read()

from rpy2.robjects.packages import STAP
invlogit = STAP(string, "invlogit")

ro.r.curve(transform(ro.r.coef(fit)[0] + ro.r.coef(fit)[1]*ro.r.x), add = True)
</code></pre>

<p>In this state, <code>ro.r.curve</code> gives an error that <code>TypeError: unsupported operand type(s) for *: 'float' and 'FloatVector'</code></p>

<p>So, as per this <a href="http://stackoverflow.com/questions/3087145/multiplying-all-elements-of-a-vector-in-r">multiplying all elements of a vector in R</a>, I ran</p>

<pre><code>ro.r.curve(transform(ro.r.coef(fit)[0] + ro.r.prod(ro.r.coef(fit)[1],ro.r.x)), add = True)
</code></pre>

<p>But, now I am getting an error <code>TypeError: unsupported operand type(s) for +: 'float' and 'FloatVector'</code></p>

<p>Before I waste any more time figuring out how to add a scalar to a vector, I was wondering if there was a more efficient way of achieving my end goal.</p>

<p>Use the accessor "R-operator" (<code>.ro</code> - see <a href="http://rpy2.readthedocs.io/en/version_2.8.x/vector.html#operators" rel="nofollow">http://rpy2.readthedocs.io/en/version_2.8.x/vector.html#operators</a>):</p>

<pre><code>In [1]: from rpy2.robjects.vectors import FloatVector

In [2]: FloatVector((1,2,3)).ro + 2
Out[2]: 
R object with classes: ('numeric',) mapped to:
&lt;FloatVector - Python:0x7fde744c0308 / R:0x44db740&gt;
[3.000000, 4.000000, 5.000000]
</code></pre>

python plot curve rpy2