How to use if statement to compare strings

So I have an input statement to enter a gender that asks the user to input m for male and f for female. I only want the user to input either m or f. I have:

if genderInput  ~= m || genderInput ~= f
    genderInput = input('Please enter a valid input.\n');
end

but it doesn't work. Why doesn't it work?

[Dennis]

it is not clear if m and f are the strings you want to compare with or if they are variables holding the string.

For comparing strings in the first place you might want to use

strcmp or strcmpi

Answer 1

[Bruno Luong]

if isempty(genderInput) || (lower(genderInput(1))  ~= 'm' || lower(genderInput(1)) ~= 'f')
    genderInput = input('Please enter a valid input.\n');
end

[Bruno Luong]

The code can accept both format short ('m' 'f'} or long {'male' 'female'}, lower-case as well as upper-case based on the first character.

Answer 2

[Stephen23]

gI = '';
while ~ismember(gI,{'m','f'})
    gI = input('Enter gender: ','s');
end