Thank you Tony

So if I understand well an excel range of 2 columns and 3 rows will be an array looking like this : [[1,2],[3,4],[5,6]] for PYXLL

If I need it to be an array of 2 lists of length 3 I need to transpose the XL range : [[1,3,5],[2.4.6]]

If I have an interest rates curve looking like this [[date1,date2,date3],[rate1,rate2,rate3]]

and a function to interpolate between the curve points I should put [date.i] in a row and [rate.i] in a row below

if I have [datei] in a clolumn and [ratei] in a column next to it I need to transpose it

Thank You again