Regular Expressions 101

<LastName>the literal text <LastName> (case sensitive)

Group 1(\w+)

\w+any word character, repeated at least once

<the literal < (60₁₀ / 74₈ / 3C₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

LastName>the literal text LastName> (case sensitive)

Negative Lookahead(?!.*<LastName>\1<\/LastName>)

.*any character, repeated any number of times

<LastName>the literal text <LastName> (case sensitive)

\1the text saved by group 1

<the literal < (60₁₀ / 74₈ / 3C₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

LastName>the literal text LastName> (case sensitive)

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

s modifier: single line. Allows a dot to match line terminators

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

<LastName>(\w+)<\/LastName>(?!.*<LastName>\1<\/LastName>)

New

                  <LastName>Adams</LastName>
                  <LastName>Adams</LastName>
                  <LastName>Yellow</LastName>