Delete last 4 characters in a string variable

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Ryan
Ryan 2011-3-29
评论： Eli Cuellar 2019-1-30
In my script, I have used the 'uigetfile' function to acquire the FileName and PathName of a .txt file in order to read it. Later in the script I need to parse that file and write the parsed information to another .txt file. I want to name the file I am writing to to a similar name as the file I'm reading from. Example:
Open/read from: C:\Documents and Settings\blah\TestFile.txt
Write/parsed to: C:\Documents and Settings\blah\TestFileParsed.txt
Basically how do I delete the last four characters in a string variable? Thanks for the help!

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采纳的回答

Matt Fig
Matt Fig 2011-3-29
For example:
S = 'Mystringname.txt'
S = S(1:end-4)
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Ian Mclennan
Ian Mclennan 2018-11-15
I love how you changed your picture after this whole discussion. Anyways, 7 years after this discussion ended you helped me out. Thank you.
Eli Cuellar
Eli Cuellar 2019-1-30
Just for the sake of correctness, the accepted answer is applicable to character vectors.
The answer would not work for an actual string, which is initialized using double quotes as opposed to the single quotes used to initialize character arrays. The following code will produce an error:
S = "Mystringname.txt"
S = S(1:end-4)
You can check the type of a variable using
class(my_variable)

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更多回答（2 个）

Walter Roberson
Walter Roberson 2011-3-29
Locating and removing the suffix:
idx = find(ismember(S,'./\:'),1,'last');
if S(idx) == '.'; S(idx:end) = []; end
The above includes protections against the possibility that the final component of the path does not include a '.'
If you are sure as sure as sure can be that the final component includes a '.', then
S(find(S=='.',1,'last'):end) = [];
  1 个评论
Alexei
Alexei 2014-7-30
Hi! I'm just curious to learn more about your suggestion. First, why did you include
'./\:'
in the string to compare S to, instead of just
'.'
?
Aren't we only interested in the period? It seems to me it should be
idx = find(ismember(S,'.'),1,'last');
Secondly, what is the benefit to using it this way of wrapping the find() function around the ismember() function, instead of using strfind() function?
Thanks

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Steven Lord
Steven Lord 2018-11-15
If you just want to remove the extension, break the filename into its parts using fileparts.
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Walter Roberson
Walter Roberson 2018-11-16
fileparts is good because it does not assume that the extension is 3 characters long.

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