how to extract double value from a string?

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Happy PhD
Happy PhD 2023-2-17
评论： Luca Ferro 2023-2-17
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

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采纳的回答

Dyuman Joshi
Dyuman Joshi 2023-2-17
移动：Star Strider 2023-2-17
Ran in:
"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

更多回答（1 个）

Luca Ferro
Luca Ferro 2023-2-17
编辑：Luca Ferro 2023-2-17
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)
  2 个评论
VBBV
VBBV 2023-2-17
Ran in:
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

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