Category Archives: Arrays

Extracting numbers from text and regular expressions

Posted on 30/11/2014 by dougaj4

Daily Dose of Excel recently had a post on extracting a number from a specified position in a text string, using mega-in-sheet-formulas like: This reminded me of a post from earlier this year, which provided a User Defined Function (UDF) … Continue reading →

Posted in Arrays, Excel, UDFs, VBA | Tagged , , , , | 4 Comments

Solving polynomials – update

Posted on 14/08/2014 by dougaj4

The polynomial spreadsheet (details here) provides functions to solve polynomial equations of any order; using an “exact” method for up to quartic, and an iterative procedure for higher orders.  The input for the functions requires the equation coefficients to be … Continue reading →

Posted in Arrays, Excel, Maths, UDFs, VBA | Tagged , , , , , | 1 Comment

Alglib/Python spline functions update

Posted on 02/08/2014 by dougaj4

The Excel Spline-Matrix spreadsheet has now been updated with several new spline interpolation functions.  See Alglib/Python linear and non-linear fitting functions for links to download and install the necessary Excel-Python and Alglib files.  Also required is Python version 2.7 or 2.6. The … Continue reading →

Posted in AlgLib, Arrays, Excel, Link to Python, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , , , | 2 Comments

Evaluating text and Integration with Python and ALGLIB

Posted on 07/07/2014 by dougaj4

Following the previous post on evaluating mathematical functions entered as text on the spreadsheet, I have now written a spreadsheet with similar functionality using Python functions, and the Excel-Python add-in.  Also included are integration functions using the SciPy Python library, … Continue reading →

Posted in AlgLib, Arrays, Excel, Link to Python, Maths, Newton, Numerical integration, NumPy and SciPy, UDFs, VBA | Tagged , , , , , , | 1 Comment

Data Transfer to Python – Update

Posted on 08/06/2014 by dougaj4

As noted in the comments here, the main bottleneck in the Python matrix solver functions presented recently was not in the data transfer from Excel, but rather in the creation of the Numpy arrays for very long lists of short … Continue reading →

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