How I convert a str to Num, and label them. please help me.

Dear Sir/Madam,

I am a beginner of MATLAB please help me, here is my prog. the below program i want to convert a string into number want a label by connecting diffident string like.

Function num_arr=convert_to_num420(str_cell_arr) 
   num_arr=zeros(length(str_cell_arr),1);
   strs=unique(str_cell_arr); 

for i=1:length(str_cell_arr)
    for j=1:length(strs)
        if strcmp(str_cell_arr{i},'normal.')  
           num_arr(i)= 1;  % upto here prog is fine but next line i got error  "like too many parameters"  
"sir here i want to convert all the string into num. that is equal to 2"  below line.        

if strcmp(str_cell_arr{i},'back.','land.','neptune.','pod.','smurf.','teardrop.')                 
               num_arr(i)= 2;
           break;    
        else
             num_arr(i)= -1;
           end 
       end
    end    
end

Answer 1

[Stephen23]

Perhaps you are looking for something like this:

function num_arr = convert_to_num420(str_cell_arr)
num_arr = zeros(size(str_cell_arr))-1;
num_arr(strcmp(str_cell_arr,'normal.')) = 1;
X = {'back.','land.','neptune.','pod.','smurf.','teardrop.'};
for k = 1:numel(X)
    num_arr(strcmp(str_cell_arr,X{k})) = 2;
end
end

And tested:

>> convert_to_num420({'normal.'})
ans =  1
>> convert_to_num420({'back.','normal.','smurf.','false!'})
ans =  2   1   2  -1

[Rehan Ali]

Thanks Sir, in my vector i have also a 3,4,5 class , how i can do? {'ftp.','guess_password.','map.','multihop.', 'phf.' , 'spy.' , 'warezclient.' , 'warezmaster.'} = 3 and {'buffer_overflow.','perl.','loadmodule.', 'rootkit.'} = 4

{'ipsweep.','nmap.', 'portsweep.','satan'} = 5

kindly tell me.

[Guillaume]

In cases like this I would create a map, either using containers.Map or simply with a cell array, between strings and numbers and use ismember for converting from string to number:

function num_arr = convert_to_num420(str_cell_arr)
   map = {'normal.'     1
          'back.'       2
          'land.'       2
          'neptune.'    2
          'pod.'        2
          'smurf.'      2
          'teardrop.'   2};
   num_arr = zeros(size(str_cell_arr))-1; %assuming you want -1 for not found
   [found, index] = ismember(str_cell_arr, map(:,1));
   num_arr(found) = cell2mat(map(index(found), 2));
end

It's more extensible, and the mapping a lot more obvious.

[Rehan Ali]

function num_arr = convert_to_num420003m(str_cell_arr) map = {'normal.' 1 'back.' 2 'land.' 2 'neptune.' 2 'pod.' 2 'smurf.' 2 'teardrop.' 2 ' ftp_write.' 3 'guess_passwd.' 3 'nmap.' 3 'multihop.' 3 'phy.' 3 'spy.' 3 'warezclient.' 3 'warezmaster.' 3 'buffer_overflow.' 4 'perl.' 4 'loadmodule.' 4 'rootkit.' 4 'ipsweep.' 5 'nmap.' 5 'portsweep.' 5 'satan.' 5}; num_arr = zeros(size(str_cell_arr))-1; %assuming you want -1 for not found [found, index] = ismember(str_cell_arr, map(:,1)); num_arr(found) = cell2mat(map(index(found), 2)); num_arr(found) = cell2mat(map(index(found), 3)); num_arr(found) = cell2mat(map(index(found), 4)); num_arr(found) = cell2mat(map(index(found), 5)); end

I want to this way , my vector like this. i run this prog, i got an error sir help me please.

[Rehan Ali]

Thanks Sir it is working now, i have just little bit confusion , now it if fine.

Answer 2

[Walter Roberson]

if ismember(str_cell_arr{i}, {'back.', 'land.', 'neptune.', 'pod.', 'smurf.', 'teardrop.'})

[Rehan Ali]

Sir there is no convergence. i got only 0 and 1, i need normal=1 and all other string equal to 2.

[Walter Roberson]

What is some sample input that you are calling the routine with?

[Rehan Ali]

these are different attacks related to class 2. the name of class is DOS. i want to label them all is 2. str2num.

[Rehan Ali]

i have also post my program. plz check that.