This is regex for website url matching scheme,host,port,path and query. I did it because in c#, class Uri does not understand urls without scheme and says that 'google.com' is invalid url.

parses accept language http header groups: language code iso-693-1 without country specification preference quality value

Pipe tables format for R Markdown

Regex for date in ISO 8601 format that also check the number of day in a month to be sure the date is valid

Validates IPv4 IP Address

break the code to first opening parenthesis and then closing use the groups individually not entirely . This is 40% correct online pattern but mixing it with first open then close groups in two different matches result in 100% success

Extract brazilian DDD and phone number

vyhledani netisknutelnych znaku .rlike("[\\x00-\\x1F\\x7F]")

12 characters minimum at least 1 capital letter at leat 1 minuscule letter at least 1 number at least 1 special character