How can I find the number of letters in a string? Just letters (A-Z, a-z)?

2015 5 23
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更新时间：2015 5 24
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Star Strider
Star Strider 2015-5-23

3 个投票

Easiest way:
string = 'This is a string.';
NrLtrs = length(regexpi(string, '[a-zA-Z]'));
The number of letters only is returned in the ‘NrLtrs’ variable.

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I have a question about text files. how to calculate the total number of letters (A-Z, a-z) in the whole text file?
Star Strider
Star Strider 2015-5-23
I would believe the same way. The text file would have to be in the same variable, so you would have to read the entire file in first.
I did like this but it gives error:
fid = fopen(filename, 'rt');
if fid < 0
-1;
return;
end
s = textscan(fid,'%s','Delimiter','\n');
num = length(regexpi(s, '[a-zA-Z]'));
fclose(fid);
disp(num);
Error using regexpi
All cells must be strings.
Error in letter_counter (line 8)
num = length(regexpi(s, '[a-zA-Z]'));
Image Analyst
Image Analyst 2015-5-23
Why are you using textscan to simply get a string. That's too overkill for a simple case like this. Simply use fgetl() if you want to get line by line, or use fread() if you want to suck up the whole file in one shot.
Star Strider
Star Strider 2015-5-24
If it’s a cell, address it as a cell:
string = {'This is a string.'};
NrLtrs = length(regexpi(string{1}, '[a-zA-Z]'));
You will likely have to experiment with this idea in the context of your code to get the result you want.

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