Extracting number from a string

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captainmariah
captainmariah 2021-3-30
编辑： Stephen23 2021-3-30
Hi, I want to extact the number from this string.
res_str ='TotalPower:9,7406E+00Watts'
I used below to find the index of the semi-colon, but how can I get the number from this format?
index = strfind(res_str, ':')-1
theNumber = str2double(res_str(index:21)) % - gives just NAN
Want to find the number positions (the start and end of the number, i.e. pos 12 and 21 in this case) and convert this to a number 9.7406E00
theNumber = (res_str(12:21))
theNumber =
'9,7406E+00'
Many thanks

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Stephen23
Stephen23 2021-3-30
Ran in:
str = 'TotalPower:9,7406E+00Watts';
num = sscanf(strrep(str,',','.'),'%*[^:]:%f')
num = 9.7406
  2 个评论
captainmariah
captainmariah 2021-3-30
编辑：captainmariah 2021-3-30
Thank you, I managed to get the number after some fail and trial, but its not as sleek as this code. My attempt.
index1 = strfind(res_str, ':')+1;
index2 = strfind(res_str, 'W')-1;
theNumber = res_str(index1:index2);
totalPower=str2double(theNumber);
What does this part do?
%*[^:]:%f
Stephen23
Stephen23 2021-3-30
编辑：Stephen23 2021-3-30
"What does this part do?"
That defines the format for extracting data from the string: read the sscanf documentation to know more.
... %*[^:]:%f Three distinct parts of the format string:
... %*[^:] Read and discard all non-colon characters
... : Literal colon character
... %f Read number, including optional exponent

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