Use part of a variable (substring?)

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Is it possible to only use a part of a variable? I have a variable filled with like “aabbcc”. Now I only want to use the “bb” (maybe substring?)

@Gratizzz I don’t think this is possible right now or I am missing something on the undocumented magic of variable expressions.

If it is not supported it might be added by providing a function, e.g. a function to create a substring from a given variable value or more generally a function which the possibility to match a regular expression and returning the matched string (which may be a substring) of the given value.

you can use node-red for this. There you can create a function (in JavaScript) that does this

@rikki78 thanks mate! I’ll try this out

@Gratizzz Following up on my previous post there is no undocumented magic for variable expressions. Thus, I have implemented a subString function which can be used as part of variable expressions. A regular expression (optionally with capture groups and flags) can be provided to filter the substring. Say, you want to return the third and forth character of your variable $someVariable = “aabbcc" this can be done as follows: subString($someVariable, "..(..)").

The feature will be published with the next release of pimatic.

very nice!! marcus can you please provide some more examples how to use this new feature then?

@mwittig wow! cooool thanks mate I’ll try it out when possible

@Gratizzz You’re welcome! The feature has been released as part of pimatic 0.9.39.

As @leader21 suggested, I have compiled a few usage examples. As we currently don’t have a spot for the documentation of variable functions, I have started a “how to” article on using String Expressions and String Functions for Variables & Rules.