Who can help me with defining a regular expression?

I have lines of text that might look like this:

@5%

or

@2.5%

I would like to extract everything between '@' and '%'. The text in between these characters represents a number. Sometimes, the number contains a digit, and sometimes not.

Can anyone help me with a regular expression (so I can use the function regexp) to do so?

Many thanks already.

Answer 1

[George]

str1 = '@5%';
str2 = '@2.5%';
regex = '\d*\.?\d+';
[s1 e1] = regexp(str1, regex);
[s2 e2] = regexp(str2, regex);

str1(s1:e1)
str2(s2:e2)

>> ans =

5

>> ans =

2.5

Play around with this. The regex captures 0 or more digits, 0 or 1 dots, and one or more digit. It ignores the @ and % signs. There are possibly weird cases where it may not work.

[George]

Warning, it will match on digits that aren't surrounded by the @ and % signs. If that's important you can modify the regex and adjust the ranges like str1(s1+1:e1-1).