Delete last 4 characters in a string variable

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!

Answer 1

[Matt Fig]

For example:

S = 'Mystringname.txt'
S = S(1:end-4)

[Ryan]

You, sir, are a steely-eyed MatLab genius.

[Walter Roberson]

How can you tell? From his picture, I'd say he looks more like a brown-eyed MATLAB genius.

[Matt Fig]

Or at least a brown-eyed MATLAB fan.

[Ryan]

It's from his expression on his face. He just has that "yep, I'm a MatLab Genius" smirk.

[Walter Roberson]

Yeh, but the question is how you can tell he is steely-eyed instead of brown-eyed ?

[Ian Mclennan]

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]

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)

Answer 2

[Walter Roberson]

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) = [];

[Alexei]

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

Answer 3

[Steven Lord]

If you just want to remove the extension, break the filename into its parts using fileparts.

[Walter Roberson]

fileparts is good because it does not assume that the extension is 3 characters long.