How can I assign numeric values to strings in an array?

I need to assign specific values to some of these chemical species in an array. I need to set RH equal to 100, OH = 100, and NO = 100 and the rest of the species are equal to 0. The array of species looks like this:

 SpeciesName = 

    'RH'
    'OH'
    'RO2'
    'H2O'
    'NO'
    'NO2'
    'RCHO'
    'HO2'
    'HNO3'
    'H2O2'
    'O2'
    'ROOH'
    'hv'
    'O3'

Answer 1

[Thorsten]

You can use a structure

S = struct('Name', {{'RH' 'OH' 'RO2' 'H20'}}, 'Value', [100 100 0 0])

Answer 2

[Stephen23]

SpeciesName = {
    'RH'
    'OH'
    'RO2'
    'H2O'
    'NO'
    'NO2'
    'RCHO'
    'HO2'
    'HNO3'
    'H2O2'
    'O2'
    'ROOH'
    'hv'
    'O3'};
C = SpeciesName';
C(2,:) = num2cell(zeros(size(C)));
C(2,1:2) = {100};
S = struct(C{:});

And accessing the data in the structure is trivial:

>> S.O2
ans =
     0
>> S.RH
ans =
   100
>> S.NO
ans =
     0