Spread.NET 17 Formula Reference
Formula Functions / Functions H to L / LAMBDA
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    This function can be used to create custom, reusable functions and call them by a desired name. You can create functions for commonly used formulas and effectively add your own functions.


    LAMBDA([parameter1, parameter2, …,] calculation)


    This function has the following arguments:

    Argument Description
    parameter [Optional] A value that you want to pass to the function, such as a cell reference, string or number. You can enter up to 253 parameters.

    [Required] The formula you want to execute and return as the result of the function. It must be the last argument and it must return a result.


    Data Types

    The concise format returns a text value, whereas the strict format returns an array of the same size and shape as the input.


    The following sample code show the basic usage of LAMBDA function.

    Copy Code
    IWorkbook workbook = fpSpread1.AsWorkbook();
    workbook.Names.Add("HEAD", "LAMBDA(str, IF(str=\"\",\"error: HEAD of empty string\",LEFT(str,1)))");
    workbook.Names.Add("TAIL", "LAMBDA(str, IF(str=\"\",\"error: TAIL of empty string\",RIGHT(str,LEN(str)-1)))");
    workbook.Names.Add("REVERSE", "LAMBDA(str,IF(str=\"\",\"\",REVERSE(TAIL(str))&HEAD(str)))");
    IWorksheet sheet1 = workbook.Worksheets[0];
    sheet1.Cells["A1"].Value = 12345;
    sheet1.Cells["B1"].Formula2 = "HEAD(A1)";
    sheet1.Cells["C1"].Formula2 = "TAIL(A1)";
    sheet1.Cells["D1"].Formula2 = "REVERSE(A1)";
    sheet1.Cells["B2:D2"].Formula2 = "FORMULATEXT(B1)";
    sheet1.Cells["F1"].Formula2 = "LAMBDA(x, x+122)(1)";

    The output of above code will look like below:

    Version Available

    This function is available in product version 15 or later.

    Lambda Helper Functions

    Spread also supports seven new LAMBDA helper functions. These functions help in the authoring of re-usable LAMBDA functions and also serve as stand-alone functions themselves. For more information, refer:

    1. BYROW

    2. BYCOL



    5. MAP

    6. REDUCE

    7. SCAN