How to find all the words contains certain letter from a text file?

Suppose I have a text file and I want to find all the words that contain letter d(just lowercase). How do I implement this in Matlab?

[Stephen23]

Read about regular expressions:

https://www.mathworks.com/help/matlab/ref/regexp.html

To practice using regular expressions download my FEX tool:

https://www.mathworks.com/matlabcentral/fileexchange/48930-interactive-regular-expression-tool

Answer 1

[OCDER]

Try the following code for opening a file and looking for a word with lower case d.

FID = fopen('filename.txt', 'r'); %Open a file to read

Pattern = '\w*d+\w*'; %regexp search pattern for a word with lower case d
                      % \w*   any alphabet letter (\w), 0 or more (*)
                      % d+    any lowercase d (d), 1 or more (+)
WordList = {}; %Stores all the words with d in it
WordLine = []; %Stores all the line number for each word that has d in it
Line = 1; %Line number to read
while feof(FID) == 0 %Check if the end of file has not been reached
    GetText = fgetl(FID); %Read the next line of the file
    FoundWord = regexp(GetText, Pattern, 'match'); %Search for all words that match the Pattern in the GetText string
    if ~isempty(FoundWord) 
        WordList = [WordList; FoundWord']; %Add the found word to the list
        WordLine = [WordLine; Line*ones(length(FoundWord), 1)]; %Save the line number where the word was found
    end
    Line = Line +1;
end

fclose(FID);    %Close the file that was read to free up memory

[num2cell(WordLine) WordList] %Show the output in matlab