regexp with _ recognized as a letter

when you use regexp regexp(Date, '(?<=Month=)\w+', 'match')

Date=Year2012_MonthMay_Day05

this character '_' is recognized as a letter??? so the information of the month can not be separated properly

Answer 1

[Walter Roberson]

\w does not match "letters"

https://www.mathworks.com/help/matlab/ref/regexp.html#input_argument_d0e853509

"\w Any alphabetic, numeric, or underscore character. For English character sets, \w is equivalent to [a-zA-Z_0-9]"

If you want to match English letters then use [a-zA-Z]

[Luca cadalo]

so, in that case, you can not use \w

[Guillaume]

No you cannot use \w. It's trivial to replace it with something that would work. I assume

   regexp(Date, '(?<=Month)[^_]+', 'match')

would probably work for you. Note that I've removed the = you had after Month since it would have failed to match your example string.