Displaying All the Related Items from an Input File

I am working on a program where I have to read a text file data.txt which has content like this:

Mango Guava

Banana

Pears Strawberry

Guava Watermelon

Coconut Guava

Here, Mango is related to Guava, Banana is not related to anyone, Pears is related to strawberry, Guava is related to Watermelon, and Coconut is related is Guava.

Now, the aim of the program is to check the second string of each row (if present) (i.e., Guava) with the first string in the first column (only) and if present display its relation altogether. The output of the program should be:

Mango Guava Watermelon

Banana

Pears Strawberry

Coconut Guava Watermelon

Here is what i have tried. I have read the file data and split it into 2 cell array and stored it in B and C. How should i go further to check the relations and dispay the output. Your help would be appreciated.

fid=fopen('data.txt');
tline = fgetl(fid);
tlines = cell(0,1);
while ischar(tline)
    tlines{end+1,1} = tline;
    tline = fgetl(fid);
end

D = regexp(tlines, '\s+', 'split');
A = vertcat(D{:});

for i= 1:length(A)
    t = strsplit(A{i}) ;
    b{i} = t{1} ;
end
B=b'; 

for j= 1:length(A)
    s = strsplit(A{j,2}) ;
    c{j} = s{1} ;
end
C=c';

Answer 1

[Ameer Hamza]

Try this

str = fileread('test.txt');

str_words = cellfun(@(x) {strsplit(x, ' ')}, strsplit(str, '\n'));
str_words = [vertcat(str_words{:}) repmat({''}, size(str_words, 2), 1)];

[tf, idx] = ismember(str_words(:,2), str_words(:,1));
str_words(tf, 3) = str_words(idx(tf), 2);

str_words = str_words.';
sprintf('%s %s %s\n', str_words{:})

Result

ans =
    'Mango Guava Watermelon
     Banana  
     Pears Strawberry 
     Guava Watermelon 
     Coconut Guava Watermelon
     '

[Glorit P.]

Hi Ameer,

Thank you for your quick response. I tried your solution. I get the followng error:

Error using vertcat

Dimensions of matrices being concatenated are not consistent.

Also, I do not want Coconut Guava Watermelon in the last line.

I just want the output should be:

Mango Guava Watermelon

Banana

Pears Strawberry

Coconut Guava

Thank you in advance.

[Ameer Hamza]

Are you using the same input or some other input when error occur? Can you paste your code here?

Also, what is the exact rule? Why in the line 'Mango Guava', the Guava is replaced but in the line 'Coconut Guava', it is not replaced?

[Glorit P.]

Hi Ameer, I am using the same input. Here is your code, which i am trying:

It is giving the Error using vertcat

Dimensions of matrices being concatenated are not consistent.

Regarding the rule, i think you are right. The output should be

Mango Guava Watermelon

Banana

Pears Strawberry

Guava Watermelon

Coconut Guava Watermelon

Could you just help me to get rid of that vertcat error? Your help is highly appreciated.

PS: This is the data of my input file:

Mango Guava

Banana

Pears Strawberry

Guava Watermelon

Coconut Guava

str = fileread('data.txt');
str_words = cellfun(@(x) {strsplit(x, ' ')}, strsplit(str, '\n'));
str_words = [vertcat(str_words{:}) repmat({''}, size(str_words, 2), 1)];
[tf, idx] = ismember(str_words(:,2), str_words(:,1));
str_words(tf, 3) = str_words(idx(tf), 2);
str_words = str_words.';
sprintf('%s %s %s\n', str_words{:})

[Ameer Hamza]

Try this version

str = fileread('test.txt');

str_words = cellfun(@(x) {strsplit(x, ' ')}, strsplit(str, '\n'));
str_words = [reshape([str_words{:}], 2, []).' repmat({''}, size(str_words, 2), 1)];

[tf, idx] = ismember(str_words(:,2), str_words(:,1));
str_words(tf, 3) = str_words(idx(tf), 2);

str_words = str_words.';
sprintf('%s %s %s\n', str_words{:})

[Glorit P.]

Hi Ameer,

Thank you so much. It worked like charm. Really appreciate your kind help.

[Ameer Hamza]

I am glad to be of help!

[Glorit P.]

Hi Ameer,

I just noticed, that the output through the code you provided is coming Like This:

Mango Guava

Banana

Pears Strawberry

Guava Watermelon

Coconut Guava Watermelon

But, What i want output is:

Mango Guava Watermelon

Banana

Pears Strawberry

Guava Watermelon

Coconut Guava Watermelon

Do you know what is wrong here? In first line, Watermelon should be there, i.e., Mango Guava Watermelon. Thank you in advance.

[Glorit P.]

Hi Ameer,

I tried this code. And this works fine. Thank you once again for your time and help.

fid=fopen('data.txt');
tline = fgetl(fid);
str = cell(0,1);
while ischar(tline)
    str{end+1,1} = tline;
    tline = fgetl(fid);
end
D = regexp(str, '\s+', 'split');
A = vertcat(D{:});
[tf, idx] = ismember(A(:,2), A(:,1));
A(tf, 3) = A(idx(tf), 2);
A = A.';
sprintf('%s %s %s\n', A{:})

[Ameer Hamza]

I am not sure why the code in my comment didn't give the correct output. It works fine in R2020a. Good to know that you found an alternate solution.

[Glorit P.]

Hi Ameer,

I have one more question. In the program you took

str_words(tf, 3) = str_words(idx(tf), 2);

you took 3 in str_words(tf, 3), as we already know there will be 3 columns. My question is, if we want to scale up our program, where we do not know how many columns should be there as it really depends on the number of repeated items in the first column. Then how can we assign this in our program? Do you have any idea about this?

Best,

Glorit P

[Ameer Hamza]

Can you write down a small example of this general case? A small input text which requires multiple replacements and the required output.

[Glorit P.]

Hi Ameer,

An example could be like this this input:

Mango Guava

Banana

Pears Strawberry

Guava Watermelon

Coconut Guava

Watermelon Papaya

Strawberry Litchi

Papaya Jackfruit

Output:

Mango Guava Watermelon Papaya Jackfruit

Banana

Pears Strawberry Litchi

Guava Watermelon Papaya Jackfruit

Coconut Guava

Watermelon Papaya Jackfruit

Strawberry Litchi

Papaya Jackfruit

This is just an example where you can see we have 5 columns. My input list is long, therefore, i do not know how long column will be after comparing the second column of the input file with the first column.

[Ameer Hamza]

Here is a quick solution. There might be more efficient way to write this code

str = fileread('test.txt');

str_words = cellfun(@(x) {strsplit(x, ' ')}, strsplit(str, '\n'));
str_words = vertcat(str_words{:});

while true
    [tf, idx] = ismember(str_words(:,end), str_words(:,end-1));
    str_words(tf, end+1) = str_words(idx(tf), end);
    str_words(~tf, end) = deal({''});
    if all(cellfun(@isempty, str_words(:,end)))
        break;
    end
end
str_words(:,end) = [];

str_words = str_words.';
fprintf([repmat('%s ', 1, size(str_words,1)) '\n'], str_words{:})

[Glorit P.]

HI Ameer,

Thank you for the solution. When i run your code, it is giving me the output which is same as input file. There is no difference at all.

[Ameer Hamza]

Can you look at the content of cell array str_words? Is it correct or the same as the original file? Can you paste your code here.

I get the following output

Mango Guava Watermelon Papaya Jackfruit 
Banana     
Pears Strawberry Litchi   
Guava Watermelon Papaya Jackfruit  
Coconut Guava Watermelon Papaya Jackfruit 
Watermelon Papaya Jackfruit   
Strawberry Litchi    
Papaya Jackfruit    

[Glorit P.]

Hi Ameer,

For some strange reason, i do not know why it is giving me different output for the same code.

I made slight modification to your code and it is giving me the same output as required now.

Thank you very much for all your help and time. Much appreciated.

Here is a code that worked for me.

fid=fopen('data1.txt');
tline = fgetl(fid);
str = cell(0,1);
while ischar(tline)
    str{end+1,1} = tline;
    tline = fgetl(fid);
end
D = regexp(str, '\s+', 'split');
A = vertcat(D{:});
while true
    [tf, idx] = ismember(A(:,end), A(:,end-1));
    A(tf, end+1) = A(idx(tf), end);
    A(~tf, end) = deal({''});
    if all(cellfun(@isempty, A(:,end)))
        break;
    end
end
A(:,end) = [];
A = A.';
fprintf([repmat('%s ', 1, size(A,1)) '\n'], A{:})

[Ameer Hamza]

I am glad to be of help!