Iterator

In the Ultra Transcenders books

DP-600PL-300

Each book explains Iterator in context, with comparison tables and the common traps.

Terms in this definition

• DAX

  Short for Data Analysis Expressions, the formula language you write measures, calculated columns and row-level security rules in, within tabular semantic models in Power BI, Excel Power Pivot or Analysis Services.

• LIKE

  Compares strings with a pattern that can contain the % and _ wildcards. Because it only understands character patterns, searching big volumes of text this way is much slower than using full-text search.

• SUMX

  Iterates over each table row, evaluating an expression, then totals those results; text, logical values and blanks don't count.

• Event

  Table in Log Analytics where entries from Windows event logs are kept.

• Row context

  Exists automatically in calculated columns and inside iterators like SUMX, giving DAX a current row to work on. Filtering the model is left to filter context; a current row does not do that by itself.

Related terms

• AVERAGEX

  Returns the mean of an expression after computing it once for each row in a table; if the table has no rows, this DAX iterator gives BLANK.

• CONCATENATEX

  Builds one text string by computing an expression for every row of a table and stringing the results together. This DAX iterator can optionally take a separator and an order for sorting.

• COUNTAX

  A DAX iterator that evaluates an expression across a table's rows and counts how many results are not blank, logical values included.

• GEOMEAN

  A DAX statistical function giving the geometric mean of a column's numbers. Its iterator version, GEOMEANX, works out an expression row by row over a table and then does the same.

• RELATED

  Fetches a column value from the lookup table, that is the one side of a many-to-one relationship, for whichever row is being evaluated. It therefore needs to run inside an iterator or a calculated column, where row context exists.