RowExpression.From

RowExpression.From is a Power Query M function that returns the abstract syntax tree (AST) for a function’s body, normalized into a row expression. The function returns an AST if it can be generated, or an error otherwise.

Compatible with: Power BI Service Power BI Desktop Excel Microsoft 365

Syntax

RowExpression.From( function as function ) as record

Description

Returns the abstract syntax tree (AST) for the body of function, normalized into a row expression:

• The function must be a 1-argument lambda.
• All references to the function parameter are replaced with RowExpression.Row.
• All references to columns are replaced with RowExpression.Column(columnName).
• The AST will be simplified to contain only nodes of the kinds:
  • Constant
  • Invocation
  • Unary
  • Binary
  • If
  • FieldAccess
  • NotImplemented

An error is raised if a row expression AST cannot be returned for the body of function.

Examples

Returns the AST for the body of the function each [CustomerID] = "ALFKI"

RowExpression.From( each [CustomerName] = "ALFKI" )

// Output:
[
  Kind = "Binary",
  Operator = "Equals"
  Left =  [ Kind = "FieldAccess", MemberName = "CustomerName", Expression = "Record" ]
  Right = [ Kind = "Constant", Value = "ALFKI" ]
]

Related functions

Other functions related to RowExpression.From are:

• ItemExpression.From
• ItemExpression.Item
• RowExpression.Column
• RowExpression.Row

Contribute » | Contributors: Rick de Groot
Microsoft documentation: https://learn.microsoft.com/en-us/powerquery-m/rowexpression-from