what's this character?

Hi list,

I've encounter this problem (see below).? I know it's particularly R-related and it's easy to get by but it still bothers me a lot.? 


It looks the last character of "N.C. " is a space to me, but it's clearly not.? Can someone tell me a way to figure out what character is in the last position.

Thanks!

Tao

levels(dat$flag)[3]

[1] "N.C.?"

levels(dat$flag)[3]=="N.C. "

[1] FALSE

substr(levels(dat$flag)[3],5,5)

[1] "?"

substr(levels(dat$flag)[3],5,5)==" "

[1] FALSE

"N.C.?"=="N.C. "?? ## NOTE: this last one can't be reproduced after copy-n-paste

[1] FALSE