[R] searching for elements

[Chyden Finance]

Hello!

For the past three years, I have been using R extensively in my PhD  
program in Finance for statistical work.  Normally, I can figure this  
kind of thing out on my own, but I am completely stumped as to why the  
following code does not work.

I have two variables: sigs and p0_recent.

dim(sigs) = 296 3
dim(p0_recent) = 504 7

I want to compare each element in the first column of sigs with the  
elements in the first column of p0_recent.

In other words, does sigs[i,1] == p0_recent[j,1], where i = 1:dim(sigs) 
[1] and j = 1:dim(p0_recent)[1].

I've been trying:

 > for (j in 1:dim(p0_recent)[1]) {
+ for (i in 1:dim(sigs)[1]) {
+ if (sigs[i,1] == p0_recent[j,1]) {
+ print(sigs[i,1])
+ }}}

But, I get:

Error in Ops.factor(sigs[i, 1], p0_recent[j, 1]) :
   level sets of factors are different

Is there a better way than for loops to compare each element in one  
column to each element in another column of different length?  If not,  
can anyone suggest a solution?

CWE