[R] Spline Function

[Animesh Saxena]

I am using R for volatility calibration (Variance Gamma distribution). 
My question is very basic and not at all related to mathematics!

     y=spline(KK,CallPrices,,"fmm",,,strikes)

When calling spline function it returns a list y

The list contains some numbers which I have to subtract from another 
array called "MarketPrices"

since y is a list a normal subtraction is not possible.

For example I get this output from spline function...

$x
  [1] 1050 1100 1150 1175 1200 1250 1300 1350 1400 1450 1500

$y
  [1] 175.15474 146.78475 121.76502 110.50149 100.05049  81.49610  
65.87413  52.89799  42.24847  33.59852  26.63327

I can chunk out...the second list...using modelprices[2]

 > modelprices[2]
$y
  [1] 175.15474 146.78475 121.76502 110.50149 100.05049  81.49610  
65.87413  52.89799  42.24847  33.59852  26.63327

Still its a list and I think I need an array
other array is
 > marketprices
  [1] 171.4 140.4 112.8  99.8  88.2  66.9  49.5  35.7  25.2  17.0  12.2
 > marketprices-modelprices[2]
Error in marketprices - modelprices[2] :
   non-numeric argument to binary operator

Is there any way to perform this substraction?

I tried the normal approaches like
 > as.numeric(modelprices[2])
Error: (list) object cannot be coerced to type 'double'

Thanks in advance!--

Regards,
Animesh Saxena

(www.quantanalysis.in)