how to extract double value from a string?

I been trying to figure our how to extract certain numbers from a string with this layout:

D:\MATLAB\noise_check\bilder\Image_230217_1227_Temp_ 42,75.png" 

I want to extract the value 42.75 from it. Any ideas how I can do this?

I tried this but it gives me NaN as result:

V = str2double(regexp(fullFileNames,'\d+','match'))

This gives error "Error using sscanf, first argument mustnbe a text scalar".

d = sscanf(fullFileNames, '%d %d %d')

Thanks

Answer 1

[Dyuman Joshi]

"I tried this but it gives me NaN as result: "

Does it? Let's check -

str = "D:\MATLAB\noise_check\bilder\Image_230217_1227_Temp_ 42,75.png";
V = str2double(regexp(str,'\d+','match'))

V = 1×4

230217 1227 42 75

out = str2double(replace(regexp(str, '\d+,\d+', 'match'),',','.'))

out = 42.7500

[Happy PhD]

My strings are an cell array so maybe thats why it doesn't work.

Answer 2

[Luca Ferro]

assuming the string is always formatted as such you could just:

s='D:\MATLAB\noise_check\bilder\Image_230217_1227_Temp_ 42,75.png'

numS=s(end-8:end-4);

numS2D=replace(numS(',','.'); %necessary since the conversion to double needs . and not ,

numD=str2double(numS2D)

[VBBV]

s='D:\MATLAB\noise_check\bilder\Image_230217_1227_Temp_ 42,75.png'

s = 'D:\MATLAB\noise_check\bilder\Image_230217_1227_Temp_ 42,75.png'

numS=s(end-8:end-4)

numS = '42,75'

numS2D=replace(numS,',','.'); % may be you mean this 
numD=str2double(numS2D)

numD = 42.7500

[Luca Ferro]

yep, typo. Thanks for the correction