Category Archives: Link to Python

Indexing NumPy arrays with floats …

Posted on 01/04/2017 by dougaj4

… now you can’t. I recently updated to the latest version of NumPy (1.12.1), and today I discovered that some of my spreadsheets using NumPy arrays (via xlwings) were returning errors like: IndexError: only integers, slices (`:`), ellipsis (`…`), numpy.newaxis … Continue reading →

Posted in Arrays, Excel, Link to Python, NumPy and SciPy, UDFs, VBA | Tagged , , , , , | 2 Comments

The meaning of = in Python

Posted on 26/02/2017 by dougaj4

In VBA, if you have an array named a and a variant named b, then the statement “b = a” creates a new array b with the same size and values as a.  If the values of either a or b are subsequently changed, the values of the … Continue reading →

Posted in Arrays, Excel, Link to Python, NumPy and SciPy, UDFs, VBA | Tagged , , , , , , , , , | 4 Comments

Weighted Least Squares Regression, using Excel, VBA, Alglib and Python

Posted on 05/02/2017 by dougaj4

Least squares linear regression in Excel is easy.  That’s what the Linest and Trend functions do.  That is, they find the coefficients of a straight line (or higher dimension shape) so that the sum of the squares of the distances of … Continue reading →

Posted in AlgLib, Curve fitting, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA | Tagged , , , , , , | 9 Comments

Debugging with xlwings and PyCharm

Posted on 26/01/2017 by dougaj4

The xlwings documentation covers de-bugging, but it is very brief and it took me some time to get everything working, so this article covers the process in a bit more detail.  The details are affected by the editor being used, … Continue reading →

Posted in Excel, Link to Python, UDFs, VBA | Tagged , , , , , , | Leave a comment

Transferring and converting strings in Excel and Python

Posted on 26/12/2016 by dougaj4

The load table for the 3D Frame spreadsheet has a column listing the global axis for each load as text (X, Y, or Z).  In the VBA version the table is converted to a variant array, and the axes are handled … Continue reading →

Posted in Excel, Link to Python, Newton, NumPy and SciPy, VBA | Tagged , , , , , , , , | Leave a comment