Alternative missing values in readcsv?

[fw]

Is there a way to specify alternative missing values when reading a csv file?

For example, if I read the line "1,,100,0,10", the matrix will be [1 0 100 0 
10], while I would MUCH prefer to get [1 nan 100 0 10].  

I realize that i can use another program to alter the input file, but that 
seems unnecessarily painful. 

(pardon the cross posting to the matlab group, but I have a feeling I might get 
a different set of answers here...)