Python Programming: Lesson 43 - Groups in Regular Expressions смотреть онлайн

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In the previous lesson (https://youtu.be/OZuQ7F2_gU0), we introduced the concept of metacharacters. In this lesson, we will continue our exploration of regular expressions to bring up the concept of groups.

re.sub(a,b,c) replaces the regular expression a with string b in the overall string c

Metacharacters:
. matches ANY character
^ matches the beginning of a string
$ matches the end of a string

Character classes are collections of characters in square brackets that could match a particular character within a string. It is a component of a regular expression. If we use a dash -, we are looking in a range of characters, so E-H match E, F, G, or H at a particular position within a string.

print( re.findall( r"sup{2,6}" , "supsupsup" ) ) # [ "supsup" , "supsup" , "supsupsup" ]

Groups are categorized in parenthesis () within a regular expression. They can be referenced by index position, and we can reference the groups of regular expressions within a particular string to check. You can learn about the details in this videO.

0:37 Review of print( x, y, ... ) and Regular Expressions
5:40 Review of Metacharacters
8:03 NEW: Character Classes

Ready for the next video? Check out default and multiple function arguments here: https://youtu.be/kL_PPpbVXuY (lesson 44)

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