====Rename====

This layer is used to change the name of one or more captured data points using //regular expressions//.

===Parameters===

^Name^Default^Meaning^
|from||The text to search for|
|expression||//Optional// expression-based text to search for|
|to||The resulting text|

===Description===

This is most often used when you have captured data that varies in name or number.

For example, let's say we have several water pumps, named **Water Pump #1** to **Water Pump #5**. We also have a table of //incidents// that include a field that identifies which pump failed. 

When we get data for a particular incident on Pump 3, we end up capturing points like **Water Pump #3 Pressure**, **Water Pump #3 Speed** and **Water Pump #3 Voltage**. 

But if we want to directly compare incidents, it would be //much// easier if these all used the same point-names, so renaming them to just **Pump Pressure / Speed / Voltage** would be useful.

===Example===

Let's say we start with...

^Attribute^Value^
|Start Time|12:00|
|End Time|13:00|
|Pump #3 Pressure|20|
|Pump #3 Voltage|240|
|Pump #3 Speed|32.3|

...and we have the following layer...

<code javascript>
[{
    "type": "rename",
    "from": "Pump #.\s(.*)",
    "to": "Pump $1",
    "comment": "Rename Pump Data"
}]
</code>

Our final output will rename the two 'Pump #3' values so that our final attributes look like those below...

^Attribute^Value^
|Start Time|12:00|
|End Time|13:00|
|Pump Pressure|20|
|Pump Voltage|240|
|Pump Speed|32.3|

===Using Attributes In Expressions===

If you want to use attribute values in expressions, use the **expression** rather than **from** parameter.

This would allow you to use the values of captured attributes in your regular expression.