MATLAB Answers

remove numbers from a name

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mohammad
mohammad on 7 Jul 2012
There is a name that have also numbers and letters and characters like '_'. For example:
name='12345_2323_abc_cd'
Now it is needed to remove numbers. And also remove '_' if this character is between numbers (if this character is between letters should not be remove). Then "name" must convert to:
name='abc_cd'
How could I do this converting in MATLAB? Please help.

Answers (4)

Jan
Jan on 8 Jul 2012
Beside the powerful regexp methods, a simple approach:
name = '12345_2323_abc_cd';
index = find(isletter(name), 1);
name = name(index:end);
  2 Comments
Image Analyst
Image Analyst on 8 Jul 2012
But this won't give the answer you wanted for your case "a" in your comment to me, where you wanted a leading underline. Jan's method doesn't give you the underline as the first character like you asked for. You'd have to check for that case and have an "If" block (like I did) to handle whether or not to strip off the leading underline. Did you make a mistake when you explained the different cases to me?

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Mark Whirdy
Mark Whirdy on 7 Jul 2012
welcome to the frustrating world of regular expressions!!
regexp(name,'[a-z]\w+','match')
all the best,
Mark
  5 Comments
Walter Roberson
Walter Roberson on 7 Jul 2012
Your code would not remove the numbers in abcd678
Now it is needed to remove numbers.

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Walter Roberson
Walter Roberson on 7 Jul 2012
regexprep(name, '\d[0-9_]+\d', '')
This expression makes the guess that underscores should only be removed if there are digits on both sides of them, so for example in 1234_abcd this would become _abcd . This guess is supported by the wording of the Question.
On the other hand, the expression above has the weakness that multiple underscores together will be deleted if the group is between numbers. This is not supported by the wording of the Question. I think that perhaps the below would work to fix that:
regexprep(name, '\d+(?:_(?=\d))?', '')
  2 Comments
Walter Roberson
Walter Roberson on 7 Jul 2012
Hmmm, the first of those won't work either. The second might.

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Image Analyst
Image Analyst on 7 Jul 2012
Try this:
% Create the name using the only example we have.
name='12345_2323_abc_cd'
% Find locations of all the underlines.
underlineLocations = find(name == '_', 2, 'first')
% Assume numbers occur earlier than the second underline.
% We have no examples to suggest otherwise.
outputName = name(underlineLocations(2)+1:end)
  2 Comments
Image Analyst
Image Analyst on 7 Jul 2012
It's always good to give all variant of your input when you first ask the question. This will do what you asked for the examples you gave:
% Example 1
stringIn = '12345_2323_abc_cd' % want '_abc_cd'
nameOut = regexprep(stringIn, '\d[0-9_]+\d', '')
if stringIn(1) == '_'
nameOut = nameOut(2:end)
end
% Example 2
stringIn = '_abc_cd' % Want 'abc_cd'
nameOut = regexprep(stringIn, '\d[0-9_]+\d', '')
if stringIn(1) == '_'
nameOut = nameOut(2:end)
end
% Example 3
stringIn = '213231_12345_2323_abc_cd' % want '_abc_cd'
nameOut = regexprep(stringIn, '\d[0-9_]+\d', '')
if stringIn(1) == '_'
nameOut = nameOut(2:end)
end

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