Negative Lookahead Regular Expression Search

In order to run a negative lookahead regular expression search, you can enclose the string you do NOT want the searched for string to appear in front of, in parentheses with a question mark and exclamation point before the given string. So in this example this search: Albany(?!\s+NY)

. . . will find any instance in which Albany is not followed by ' NY'.

This search can be modified to find any string - .* - which does not precede the state abbreviation NY - (?:(?!NY).).$

.*(?:(?!NY).).$

regex search for between X and Y instances of characters

A regular expression search for a string between X and Y numbers can be structured by following the character search by two numbers in curley brackets separated by a comma. So this search:

\r\n[A-Za-z]{2,3}\r\n

. . . will find any instances of a word between 2 and 3 letters which is listed on one line.

regex search for one or more instances of a character set

When you add a plus sign '+' after characters identified within square brackets in a regular expression search, the search will find any instances where one or more of these characters appear. So this search:

[A-D]+[0-5]+[a-c]+

. . . will find strings which begin with one or more instances of the uppercase letters between A to D, one or more digits between 1 and 5, and end with one or more of the lowercase letters between a and c.