nsolnit

/**Cumulative sum over array*/
CSUM = LAMBDA(arr,
    SCAN(0,arr,LAMBDA(a,c,a+c)));

/**Ignores Null ref (empty, space or 0), returns "" or VAl if provided*/
IFN = LAMBDA(REF,FUN,[VAL],
IF(OR(REF="",REF=" ",REF=0),IF(ISOMITTED(VAL),"",VAL),FUN)
);

/**1D linear interpolation, set SORTED=0 for unsorted data - presorting data recommended*/

nsolnit

/**Basic 1D linear generator from 2 pts*/
LEXT = LAMBDA(X,XS,YS,
    LET(X_1,INDEX(XS,1),
        X_2, INDEX(XS,2),
        Y_1, INDEX(YS,1),
        Y_2, INDEX(YS,2),
        Y_1+(X-X_1)*(Y_2-Y_1)/(X_2-X_1)
        )
);