I've got an excel file which contains a column for sex,'F' and 'M'. 'F' means female and 'M' means male. I used xlsread() to load this data, and got multiple cells( size is 1*n,n for number of people), each cell contains a character 'F' or 'M'. I want to transfer the character to number 0 or 1, 0 means 'F' and 1 means 'M'. How can I do it?