How to replace specific characters in a cell array?

Question

Ivan Mich 2023-3-2

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1921995-how-to-replace-specific-characters-in-a-cell-array

编辑： Stephen23 2023-3-18

I have a question about a code.

I have a cell array with strings and I would like to replace the last 5 characters with another for every cell array. I tried strrep but no use.

For example I have an array:

A={'MATHIEW','NIKOLIEW','SAMIEW','SAMOURAI'}.

I would like to replace ONLY in the strings that their last 3 characters have the elen\ments: IEW, with the elements 'YAU'.

I mean that I want my final array to be:

B={'MATHYAU','NIKOLYAU','SAMYAU','SAMOURAI'}.

Could you please help me?

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the cyclist 2023-3-2

Can you give a small example of input and desired output, not just a description? When folks say "string", they often mean "character array", and it matters to the solution.

Ivan Mich 2023-3-4

编辑：Ivan Mich 2023-3-4

For example I have an array:

A={'MATHIEW','NIKOLIEW','SAMIEW','SAMOURAI'}.

I would like to replace ONLY in the strings that their last 3 characters have the elen\ments: IEW, with the elements 'YAU'.

I mean that I want my final array to be:

B={'MATHYAU','NIKOLYAU','SAMYAU','SAMOURAI'}.

Could you please help me?

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Answer 1

Image Analyst 2023-3-4

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https://ww2.mathworks.cn/matlabcentral/answers/1921995-how-to-replace-specific-characters-in-a-cell-array#answer_1185120

在 MATLAB Online 中打开

Try the function endsWith in a loop to check if the string ends with certain characters

B={'MATHIEW','NIKOLIEW','SAMIEW','SAMOURAI'}
B = 1×4 cell array
    {'MATHIEW'}    {'NIKOLIEW'}    {'SAMIEW'}    {'SAMOURAI'}
for k = 1 : numel(B)
    if endsWith(B{k}, 'IEW', 'IgnoreCase', true)
        B{k}(end-2 : end) = 'YAU';
    end
end
B % Show in command window
B = 1×4 cell array
    {'MATHYAU'}    {'NIKOLYAU'}    {'SAMYAU'}    {'SAMOURAI'}

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Ivan Mich 2023-3-12

I solved it. Thank you

Voss 2023-3-12

编辑：Voss 2023-3-12

在 MATLAB Online 中打开

B = {'MATHIEW SAMOURAI'};
B = regexprep(B,'IEW\>','YAU')
B = 1×1 cell array
    {'MATHYAU SAMOURAI'}

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Answer 2

the cyclist 2023-3-4

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https://ww2.mathworks.cn/matlabcentral/answers/1921995-how-to-replace-specific-characters-in-a-cell-array#answer_1185155

编辑：the cyclist 2023-3-4

在 MATLAB Online 中打开

With the additional description you added that clarified the problem, you can do this very easily with regexprep:

A = {'MATHIEW','NIKOLIEW','SAMIEW','SAMOURAI','IEWBLAHIEW'};
B = regexprep(A,'IEW$','YAU')
B = 1×5 cell array
    {'MATHYAU'}    {'NIKOLYAU'}    {'SAMYAU'}    {'SAMOURAI'}    {'IEWBLAHYAU'}

Note that this solution only replaces instances of IEW that occur at the end of the character array. (I added a case to illustrate that.)

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Answer 3

the cyclist 2023-3-2

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https://ww2.mathworks.cn/matlabcentral/answers/1921995-how-to-replace-specific-characters-in-a-cell-array#answer_1184045

编辑：the cyclist 2023-3-2

在 MATLAB Online 中打开

Assuming you have character array elements, and not strings, here is one way:

% Inputs
CC_in = {'abcdeABCDE','xyzFGHIJ'};
replacementStr = '12345';
% Output
CC_out = cellfun(@(x) [x(1:end-5) replacementStr],CC_in,'UniformOutput',false)
CC_out = 1×2 cell array
    {'abcde12345'}    {'xyz12345'}

This could be generalized, for example to automatically read the length of the replacement string:

% Inputs
CC_in = {'abcdeABCDE','xyzFGHIJ'};
replacementStr = '12';
% Output
L = numel(replacementStr);
CC_out = cellfun(@(x) [x(1:end-L) replacementStr],CC_in,'UniformOutput',false)
CC_out = 1×2 cell array
    {'abcdeABC12'}    {'xyzFGH12'}

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the cyclist 2023-3-2

在 MATLAB Online 中打开

Just going to tag on to this answer, that there are other methods for strings. It might be more common for strings to be stored in a string array than a cell array. (This is arguably a better approach, if you do not have mixed datatypes contents to store.)

In that case, one can use replaceBetween:

% Inputs
CS = ["abcdeABCDE","xyzFGHIJ"];
replacementStr = "12345";
% Define the string lengths, for convenience
LCS = strlength(CS);
L = strlength(replacementStr);
% Output
CS_out = replaceBetween(CS,LCS-L,LCS,replacementStr)
CS_out = 1×2 string array
    "abcd12345"    "xy12345"

Stephen23 2023-3-2

编辑：Stephen23 2023-3-3

"This is arguably a better approach"

Agreed. In fact the MATLAB documentation is even stronger even than that, it specifically recommends against storing string scalars in a cell array:

"When you have multiple strings, store them in a string array, not a cell array. ... String arrays are more efficient than cell arrays for storing and manipulating text. ... Avoid using cell arrays of strings. When you use cell arrays, you give up the performance advantages that come from using string arrays."

source: https://www.mathworks.com/help/matlab/matlab_prog/frequently-asked-questions-about-string-arrays.html

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Answer 4

Venkatanarasimha Hegde 2023-3-18

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1921995-how-to-replace-specific-characters-in-a-cell-array#answer_1195710

编辑：Venkatanarasimha Hegde 2023-3-18

在 MATLAB Online 中打开

A = {'MATHIEW','NIKOLIEW','SAMIEW','SAMOURAI','IEWBLAHIEW'};
for i = 1:length(A)
    temp = A{i};
     if strcmp(temp(end-2:end),'IEW')
         temp(end-2:end) = 'YAU';
    end
    A{i} = temp;
end
disp(A)
    {'MATHYAU'}    {'NIKOLYAU'}    {'SAMYAU'}    {'SAMOURAI'}    {'IEWBLAHYAU'}

This is a much simpler version using loops. Even beginners can try to implement such codes who don't know much about regexp or complicated constructs.