Download - The Bastards Book of Regular Expressions

Capture, Reuse 83Roosevelt, Franklin D.Walker, Mary E.Berners-Lee, Tim J.Williams, Serena J.The main variation here is that we need a third capturing group to contain the middle initial. Also,the names may contain hyphens.Find ([\w-]+), ([\w-]+) ([A-Z].)Replace $2 $3 $1A couple of notes:1. The hyphen inside square brackets has to be escaped, because, the hyphen in that context is aspecial character that acts as a range (e.g. from A to Z, as we see in the third-capturing group).2. The dot character – . – has to be escaped, because it is a special regex character. In fact, it isa very powerful character that we’ll learn about in a [later chapter]{#dot-character}.Correcting dates with capturing groupsIn a previous chapter, we encountered the problem of trying to fix the year-value on a list of dates:12/24/2012, $50.0012/25/2012, $50.0012/28/2012, $102.001/1/2012, $2012.001/2/2012, $32.001/6/2012, $52012.001/12/2012, $642.001/13/2012, $500.001/20/2013, $100.002/1/2013, $2012.20If this list is chronological, then the data-entry person forgot to go from 2012 to 2013 when Januaryrolled around.Let’s start with how we selectively target the January dates:Find 1/\d+/2012