Select part of a string

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JE101 2017-3-23

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https://ww2.mathworks.cn/matlabcentral/answers/331510-select-part-of-a-string

评论： Gina Eldridge 2022-4-4

I have a large column vector of strings. The strings vary in length. I would like to select out the last 5 characters of the actual string (i.e., I don't want 5 blank spaces that you would get by converting it to a char array and then selecting the last 5 columns).

I have a complicated way of doing this by switching between a string array and a character array and using sub2ind, but I was wondering if there is a simpler way to do this. I've tried using strtok and flip, but can't get it to do exactly what I want.

If possible, I'd like to avoid using a loop (because of the size of the array).

If you use excel, I want to do the equivalent of the RIGHT function.

Any suggestions would be much appreciated! Thanks.

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Answer 1

Stephen23 2017-3-23

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编辑：Stephen23 2017-3-23

在 MATLAB Online 中打开

A string array treats each string as being atomic, whereas you need to be able to access each character as atomic. Use cellstr to convert to a cell array of chars, and then use cellfun to extract the parts you need:

cellfun(@(s)s(end-4:end),cellstr(inp),'uni',0)

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JE101 2017-3-23

Perfect! Thanks Stephen.

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Answer 2

Steven Lord 2017-3-23

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Another approach, if you're using the string class introduced in release R2016b, is to use extractAfter.

>> animals = {'cat'; 'elephant'; 'dog'; 'hippopotamus'};
>> animalsString = string(animals);
>> lastTwoLetters = extractAfter(animalsString, strlength(animalsString)-2)
lastTwoLetters = 
  4×1 string array
    "at"
    "nt"
    "og"
    "us"