Wrap Up

Dr Andy Evans

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Special types

• Objects and operators built into the language but used only in modules:
• Ellipsis (also "..."): used chiefly in slices in modules like numpy.
• @ Used as an operator in some maths packages.

Type annotations

• Only at class and module level
  def ascii_char(num: int) -> str:
    return chr(int)


• These give the appearance of manifest typing, but can be checked only by outside code-checking software.

Efficiency

• https://docs.python.org/3/faq/programming.html#my-program-is-too-slow-how-do-i-speed-it-up
• https://wiki.python.org/moin/PythonSpeed/PerformanceTipsp

Python 2 to 3

• Converting 2 to 3:
  https://docs.python.org/3/library/2to3.html
• If you need a particular python version or library, use a virtual environment:
  https://docs.python.org/3/tutorial/venv.html
  or Conda:
  http://www.wilsonsayreslab.org/blog/2015/10/26/managing-multiple-python-environments-using-anaconda
  https://conda.io/docs/user-guide/tasks/manage-environments.html

Other languages

• C++ / C / Java / JavaScript / C# / VB.Net / Scala: "C" Family. Broadly speaking more formal languages than Python, with more restrictions to prevent errors including manifest typing. Typical Java:
  import java.util.Vector;
public static void main (String args[]) {
    Vector v = new Vector();
    double sum = 0;
    for (int i = 0; i < 10; i++) {
        double a = Math.random()*10.0;
        sum += a
        v.add(a)
    }
    System.out.println("sum = " + sum);
}

Other useful languages:

• In vague order of usefulness:
  JavaScript (Web programming)
  PHP (Backend web processing)
  Java (General programming; Android)
  C++ (General programming; joining the godhead)
  C (Hardware programming)
  R (Statistics)
  VBA (Visual Basic for Applications)
  VB.Net / C# (Windows programming)
  Perl (Largely superseded by PHP)
  Swift / Objective C (Mac programming languages)
  Ruby (More OOP Python-like language)
  MatLab (Maths processing)
  Fortran (frequently used for mathematically intense science)
  (...though there's no good reason for it)
  Prolog (Logic programming)
  Groovy / Scala (Python-like language / Java-like language that run on the Java platform)
  Lisp / Haskell (Semi-historical lambda-based/functional languages)
  Smalltalk (Semi-historical OOP language)

Further information

• The website for subjects we've covered:
  • All the lectures.
  • Examples, practice pieces, and useful links.
• http://www.geog.leeds.ac.uk/courses/computing/

Other info

https://docs.python.org/3/howto/index.html
See also recipes in docs

Main thing

• Practice!