Regular expressions are used to identify the property of 
the object which does not have the constant name or value. 

For example, if there is an object displays the name as 
Object1, Object2,.....ObjectN means we can use the regular 
expression.

for dynamic changing text value we can use regular expression.
For expample:if build 1 the hyberlink text is< Home > and
build 2 that hyperlink text is changed to <At Home> at this
conditication using normal method object identation get fail
because of the text value varies from build to build if we
use regular expression it will pass.

Regular Expression is nothing but varying values

regular expressions are usd to identify objects/strings 
with varying values.