filter string in the string

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Liger
Liger 2019-8-21
评论： Liger 2019-8-28
Hello,
I am quietly new with matlab script.
I have a string as example.
str = 'this matlab is a good software, it is a version 9.4 which is equal to 2018a'
objective, I want to filter the number from that string ( so it is "9.4").
Note that I cannot see that number. All i want is to scan that number and show in my workspace.
so the scribt should read the text and identify the number of the version and show in my workspace.
I appreciate your help.
Regards,
LN
  2 个评论
Ted Shultz
Ted Shultz 2019-8-21
Do you not want to also get '2018'? What rule would the code use to exclude this?
Adam
Adam 2019-8-21
doc regexp
should help do this. It takes a bit of getting used to parameterising regular expressions though. There are likely simpler ways depending how robust you want it to be.

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采纳的回答

Stephan
Stephan 2019-8-21
编辑：Stephan 2019-8-21
str = 'this matlab is a good software, it is a version 9.4 which is equal to 2018a'
str = char(str);
idx = find((uint8(str)>=48 & uint8(str)<=57) | uint8(str)==46 | uint8(str)==32);
res = split(string(str(idx))," ");
res(res=="")=[]
The second line makes sure that it also works with:
str = "this matlab is a good software, it is a version 9.4 which is equal to 2018a"
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Stephan
Stephan 2019-8-21
thank you for the hint!
Liger
Liger 2019-8-28
Thank you, i found the anwser so useful
Guillaume
Stephan

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更多回答（2 个）

Stephen23
Stephen23 2019-8-21
编辑：Stephen23 2019-8-21
>> str = 'this matlab is a good software, it is a version 9.4 which is equal to 2018a';
>> out = regexp(str,'\d+\.\d+','match','once')
out = 9.4
https://www.mathworks.com/help/matlab/matlab_prog/regular-expressions.html
Guillaume
Guillaume 2019-8-21
编辑：Guillaume 2019-8-21
Using a regular expression:
numbers = regexp(youstring, '\<\d*\.?\d+\>', 'once')
which will extract any number not attached to text. Allowed formats for number is 123, 123.45, .123

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