====== Variables ======

You can store the results of mapping rules in variables to retrieve them later. Variables must be preceded by a $. When assigning a variable, you should specify the variable with two $$ ($$)  (z.B. [[en:transformation:mappings:funktionen:excel:loadtab|]]) characters, in which case the value to be stored is not saved as a string. An example:
^Rulename ^Selection ^Target ^
| r_rule   | substring(@Gtin,1,7)='99999'     | $InvalidEan  |

After the evaluation, for example, the variable $InvalidEan contains the value' false' and a further vertgleich must then check for' true' or' false', because since $InvalidEan is not empty, the following is always true.
^Rulename ^Selection ^Target ^
| rs_ruleset   | $InvalidEan |  |

If you use $$InvalidEan instead, the boolean value is in the variable.
^Rulename ^Selection ^Target ^
| r_rule   | substring(@Gtin,1,7)='9999999'     | $$InvalidEan  |

Furthermore, whole structure turn can be stored in variables, e. g. results of GroupByEx, etc.

==== remarks ====

=== reset ===

To delete or reset the object, use the function [[en:transformation:mappings:funktionen:allgemein:clearvariable|]]. An assignment with an empty string fails because an empty selector leads to a non-evaluation. This means that the following rule is not even executed:
^Rulename ^Selection ^Target ^
| r_rule   | '' | $$InvalidEan  |

=== selection  ===

The variable must always be read with exactly one dollar sign or, even better, with the function [[transformation:mappings:variablen:xvar|XVar]], This is considerably faster than direct access, e. g. in a loop, when multiple readouts are performed.