Regular Expressions 101

Pro

1st Alternative(?i)(?<!John\s)Smith

(?i)applies the following effective flags to the remainder of the pattern: gmi

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Negative Lookbehind(?<!John\s)

Johnthe literal text John (case insensitive)

\sany whitespace character

Smith the literal text Smith (case insensitive)

2nd Alternative(?i)(Smith.*\s(?!John))

(?i)applies the following effective flags to the remainder of the pattern: gmi

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

Group 1(Smith.*\s(?!John))

Smiththe literal text Smith (case insensitive)

.*any character (except for line terminators), repeated any number of times

\sany whitespace character

Negative Lookahead(?!John)

Johnthe literal text John (case insensitive)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

25 tokens

(?i)(?<!John\s)Smith |(?i)(Smith.*\s(?!John))

New

Smith but not if John Smith or Smith John

Smith but not if John Smith or Smith John