Translations:Expression Manager how-tos/5/en


 * 1) Expression: Anything surrounded by curly braces:
 * 2) *As long as there is no white space immediately after the opening brace or before the closing curly brace.
 * 3) *The expression content is evaluated by EM, so it can contain mathematical formulas, functions, and complex string and date processing.
 * 4) Tailoring: Sometimes called "piping". It is the process of conditionally modifying text:
 * 5) *You have access to all 'replacement fields', participant data, and response data.
 * 6) *You also have easier access to questions, answers, and their properties.
 * 7) Relevance Equation: A new question attribute controlling question visibility:
 * 8) *If there is a relevance equation, then the question is only shown if the relevance evaluates to true.
 * 9) *Internally, all array_filter and array_filter_exclude commands become subquestion-level relevance.
 * 10) SGQA:  This is how variables are named in LimeSurvey <= 1.91+
 * 11) *Stands for Survey-Group-Question-Answer
 * 12) *SGQA variable names look like 123X5X382X971, and may have sub-question suffixes.
 * 13) *These variable names are specific to the underlying S/Q/G/A database codes, so often need to be changed
 * 14) Equation Question Type: A new question type that saves calculations or reports to the database:
 * 15) *It is like a Boilerplate question, but its contents are saved to the database even if you set "Always Hide this Question".
 * 16) Question Code: This is the preferred variable name for EM:
 * 17) *This can be a descriptive name indicating the purpose of the question, making it easier to read complex logic.
 * 18) *Valid question codes should NOT start with a number, so when using the question code to number your questions, simply use "q1", or "q1a" or "g1q2".
 * 19) *This is what becomes the variable name if you export data to SPSS or R. So, if you do statistical analysis, you need to create only unique question codes.