The Regular Expression Generator helps you create a regular
expression to include in your AQL extractor. Before you begin, create
a list of examples that depict the concept behind the regular
expression that you want to generate. Collect examples into a simple
text file (*.txt), one per line.
Each example must be terminated by a newline character. If you do not
have a list of examples, alternatively you can enter them manually
into the Samples table.
About this task
A
regular expression
, also referred to as regex or regexp, provides a concise and
flexible means for matching strings of text, such as particular
characters, or words. A regular expression is written in a formal
language that can be interpreted by a
regular expression processor
, a program that examines text and returns matches to provided
specifications.
Procedure
- Generate
a new regular expression:
- Click Regular Expression Generator on the InfoSphere® BigInsights™ Eclipse toolbar.
- In the Regular Expression Generator
wizard, click Load samples from
file to select your list of examples, select a regular
expression to refine, and click Next.
- Refine the
expression, and click Finish.
For details about refining the expression, see Regular
Expression Generator. The regular expression is copied to the
clipboard.
- Place your
cursor within an AQL statement where a regular expression would
appear, right-click, and select Paste.
- Generate
a regular expression to replace an existing expression. If you do
not want to replace an expression, create an empty expression marker
by using two slash (/) characters in an existing, syntactically
correct AQL statement, for example:
create view MyRegex as
extract regex // as match
from Document D;
create view MyRegexes as
extract regexes /\d+/ and // as match
from Document D;
create view MyRegexFilter as
select *
from Phone P
where MatchesRegex(//, P.number);
- Right-click
a syntactically correct regular expression between the two slash
(/) characters that surround the regular expression, and select Regular Expression Generator from the
pop-up menu. If Regular
Expression Generator is not available from the pop-up menu, your
cursor is not positioned between the two slash (/) characters
that surround a syntactically correct regular expression.
- In the Regular Expression Generator
wizard, click Load samples from
file to select your list of samples, select a regular expression
to refine, and click Next.
- Refine the
expression, and click Finish.
For details about refining the expression, see Regular
Expression Generator.
Results
The regular expression replaces the original regular expression in
the file.