Regular expression: Difference between revisions

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A [[Regular expression]] is a text pattern that describes how textual input should be parsed to retrieve a piece (or complete) of the textual input.
A [[Regular expression]] is a text pattern that describes how textual input should be parsed to retrieve a piece (or complete) of the textual input.


For regular expression we advise you to look at an internet site dedicated to regular expressions: http://www.regular-expressions.info/tutorial.html
For regular expression we advise, to learn on how to use regular expressions, at a dedicated internet site. For example: https://www.regular-expressions.info/tutorial.html


An online regular expression tester can also be used to verify the correctness of the regular expression: https://regex101.com/
An online regular expression tester can also be used to verify the correctness of the regular expression: https://regex101.com/

Revision as of 15:31, 30 January 2023

A Regular expression is a text pattern that describes how textual input should be parsed to retrieve a piece (or complete) of the textual input.

For regular expression we advise, to learn on how to use regular expressions, at a dedicated internet site. For example: https://www.regular-expressions.info/tutorial.html

An online regular expression tester can also be used to verify the correctness of the regular expression: https://regex101.com/

Configurable device drivers[edit]

In RadiMation® the Regular expressions are often used to interpret the response of a device. Several configurable device drivers, provide a possibility to specify the regular expression to convert the response on a query-command into a value.

Regular expression examples[edit]

Some examples for interpreting a response are:

Received information Regular expression Determined measurement value Note
U_L_N 325 (-?[0-9.,Ee-]+) 325 Takes the first number.
I_L1;12.34 ;(-?[0-9.,Ee-]+) 12.34 Takes the first number after ";".
THD_U_L1;;14,5 ;;(-?[0-9.,Ee-]+) 14.5 Takes the first number after ";;".
AC_FREQ;Channel1;1.23E3 ;.*;(-?[0-9.,Ee-]+) 1230 Takes the first number after the appearance of a second ";".

The correctness of the regular expression can be tested, verified and improved by using the Validate Expression tool within the configurable device driver.

ValidateExpressionTool.png

Links[edit]