regexp help

Hi, im trying to read in some numbers from some HTML:

'<br>1,020.32 mb<br>'

Im currently using regexp(string,'\d+','match'), how can i read in a number such as the one above that has a comma and a decimal point?

[Stephen23]

For developing and checking regular expressions here is an interactive helper:

http://www.mathworks.com/matlabcentral/fileexchange/48930-regular-expression-helper

Answer 1

[Walter Roberson]

regexp(string, '(\d+,)*\d+(\.\d*)?', 'match')

The above is flexible enough to support any number of leading groups of digits and commas (including no leading groups). It is also flexible enough to support the possibility that the decimal point and following digits are not present -- so it supports the equivalent of your \d+ (plain integers without commas or decimal points). Furthermore it supports a trailing decimal point with no digits afterwards.

[Edward]

Thankyou! is there any chance you can explain what that expression means? im quite new to regexp

[Ashish Uthama]

Edward, this might help you get started: http://www.mathworks.com/help/techdoc/matlab_prog/f0-42649.html#f0-42723

Breakdown:

(\d+,) -- One or more digit(s) followed by a comma

* -- zero or more instances of stuff within ()

\d+ -- One or more digit(s)

(\.\d*)-- A . (the \ is to 'escape it' since just using a . has a different meaning) followed by zero or more digit(s)

? -- zero or one instance of the stuff within ()

[Walter Roberson]

Updated link: http://www.mathworks.com/help/matlab/matlab_prog/regular-expressions.html

[Evangelos Stefanidis]

In my case I had the following string and I was interested in getting the number between -....mVPower-. That was my coding:

Sting='2021-06-08-Blank5-D150mm-R0mm-7LPM-0N2Shild-12.6mVPower-105ns-25ns-G600-C580-2Acc-60xInt-4VBins-slit10u-100Frames-NoIcorr-Polar-NoFilter.spe'

pattern1='(?<=\-)(\d+,)*\d+(\.\d*)?(?=mVPower\-)';
power=str2double(regexp(fname,pattern1,'match'));

[Stephen23]

S = '2021-06-08-Blank5-D150mm-R0mm-7LPM-0N2Shild-12.6mVPower-105ns-25ns-G600-C580-2Acc-60xInt-4VBins-slit10u-100Frames-NoIcorr-Polar-NoFilter.spe';
P = str2double(regexp(S,'\d+\.?\d*(?=mVPower)','match','once'))

P = 12.6000