[R] lapply returns NULL ?

[ce]

Dear all,

I have a list of arrays :

foo<-list(A = c(1,3), B =c(1, 2), C = c(3, 1)) 

> foo
$A
[1] 1 3

$B
[1] 1 2

$C
[1] 3 1

> if( foo$C[1] == 1 ) foo$C[1]

>  lapply(foo, function(x) if(x[1] == 1 )  x  )

$A
[1] 1 3

$B
[1] 1 2

$C
NULL

I don't want to list $C NULL  in the output. How I can do that ?