Click or drag to resize

AEval Function (Array, ICodeblock)

X#
Execute a code block for each element in an array.

Namespace:  XSharp.RT
Assembly:  XSharp.RT (in XSharp.RT.dll) Version: 2.21
Syntax
Copy
 FUNCTION AEval(
	aArray AS ARRAY,
	cbBlock AS ICodeblock
) AS ARRAY
Request Example View Source

Parameters

aArray
Type: Array
The array to traverse.
cbBlock
Type: ICodeblock
The code block to execute.

Return Value

Type: Array
A reference to aArray.
The return value of the code block or is ignored — to assign the return value to each element in the array, use the AEvalA() function.
Remarks
AEval() passes the element value and the element index as arguments. AEval() makes no assumptions about the contents of the array elements it is passing.
It is assumed that the supplied code block knows what type of data will be in each element. AEval() is similar to DBEval() which executes code for each record of a database file.
Like DBEval(), AEval() can be used as a primitive for the construction of iteration commands for both simple and complex array structures.
Tip Tip
In Visual Objects 2 different functions were introduced: AEval() and AEvalOld(). The difference between these functions was that AEval() was only calling the codeblock with one parameter (the element in the array), where AEvalOld() was also passing in a second parameter (the array index). Inside X# this difference no longer exists. So AEval() and AEvalOld() are doing the same thing in X#.
Examples
This example displays the contents of a one-dimensional array:
X#
Copy
1LOCAL aArray[6]
2AFill(aArray, "Hi All!") // Fill up all elements
3AEval(aArray, {|Element| QOut(Element)})
This example uses AEval() to display an array of file names and file sizes returned from the Directory() function:
X#
Copy
1LOCAL aFiles := Directory("*.dbf")
2LOCAL nTotal := 0
3AEval(aFiles, {|aDBFFile | QOut(PadR(aDBFFile[F_NAME], 10), ;
4        aDBFFile[F_SIZE], nTotal += aDBFFile[F_SIZE]})
5? "Total bytes:", nTotal
See Also