How to Install Numpy, SciPy, Scikit-learn, Pandas, Matplotlib, and NLTK libraries for Python 3 on Windows
24 Nov 2015 | Programming | Matplotlib • NLTK • NumPy • Pandas • Scikit • SciPy
NumPy, SciPy, Pandas, and Matplotlib are fundamental scientific computing and visualization packages with Python. Scikit-learn is a simple and efficient package for data mining and analysis in Python. NLTK (the Natural Language Toolkit) is a leading platform for building Python programs to work with human language data. However, if you are using Python on Windows, it seems not easy to install these packages. Thanks to Christoph Gohlke, who provides the non-official Python extension packages for Windows. With these unofficial packages, there is a simple way to install these libraries on Windows. Read More...

Setting up Eclipse for Java API of IBM ILOG CPLEX
14 Nov 2015 | Operations Research | Java • ILOG CPLEX
Upated on April 28, 2020 with testing on Windows 10. After installed IBM ILOG CPLEX Optimization Studio 12.6, I tried the instructions described in the IBM Knowledge Center to set up Java APIs for CPLEX and CP in Eclipse, but the instructions did not work correctly. Here is what I did to build a java project with CPLEX  and CP Java APIs in Eclipse. These steps have been done in Eclipse on Windows 7 and 10, not sure if it works for other Java IDEs or other OSs. It also assumes that the IBM ILOG CPLEX Optimization Studio has already been installed. Read More...

Join Multiple Excel Workbooks through Custom SQL Query in Tableau
28 Oct 2015 | Data Science | SQL • Tableau
Recently I came across the need of joining multiple excel files in Tableau. I did a hard research on how to do it. However, most of the instructions I found were about how to join two tabs(worksheets) in the same excel workbook. In this post, I will describe how to join multiple worksheets from different workbooks, which spent me about one hour to figure out. Please note the instructions here work for Tableau Desktop 9.0 or later. Read More...

Install and Run Jupyter (IPython) Notebook on Windows
27 Oct 2015 | Programming | Python • IPython • Jupyter Notebook
To install Jupyter Notebook, there are couple of ways. One option is using the package management platforma, like Anaconda. If you don’t want use them, you can also try the installation directly through Python. You will need Python installed on your system. I assume that, like me, you already installed the newest Python package on your Windows system and now you want to install and use the Jupyter Notebook. In this post, I describe some steps you can follow to install the Jupeter directly from Python. Read More...

A Generic Comparator Class for Java Collections.sort()
13 Jul 2015 | Programming | Java • Generics

Sort A List of Objects

As a Java programmer, I often need to sort a list of objects. If the object is a primitive type, such as String, Integer, Long, Float, Double, or Date, it is easy to use Collections.sort(). However, it is not easy to sort a list of user defined objects, which do not implement the Comparable interface, for example, a Person object, as defined below. If you want to sort a list of Person objects by id in ascending order, you hav to provide a Comparator class to encapsulate the ordering. One possible comparator class is defined below. Instead, a generic comparator class is defined in this post to sort lists of primitive as well as user defined objects, in any specified order and by any specified field(s). Read More...