filter string in the string

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

[Ted Shultz]

Do you not want to also get '2018'? What rule would the code use to exclude this?

[Adam]

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.

Answer 1

[Stephan]

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"

[Guillaume]

The conversion to uint8 is a waste of time, you could just write

idx = find((str>=48 & str<=57) | str==46 | str==32);

even clearer:

idx = find((str>='0' & str<='9') | str=='.' | str==' ');

you could also use ismember:

idx = find(ismember(str, '0123456789. '));

[Stephan]

thank you for the hint!

[Liger]

Thank you, i found the anwser so useful

Guillaume

Stephan

Answer 2

[Stephen23]

>> 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

[Liger]

Thank you

Answer 3

[Guillaume]

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