The Python Scripting Language. Slides (mostly) by: Bob Dowling Presented by: Bruce Beckles University of Cambridge Computing Service

Transcription

1 The Python Scripting Language Slides (mostly) by: Bob Dowling Presented by: Bruce Beckles University of Cambridge Computing Service 1

2 Why Python? e-science interviews basic programming skills easy access to libraries lack of time return on investment 2

3 Why Python? Social Science interviews basic programming skills easy access to libraries lack of time return on investment 3

4 Why Python? Python good first language batteries included easy to learn ubiquity Requirements basic programming skills easy access to libraries lack of time return on investment 4

5 Good first language Already widely used as a first language continuity Immediate gratification Good habits Fully featured 5

6 Programming Languages Compiled Interpreted C C++ Fortran Java Python Perl Shell scripting 6

7 Python Interpreted language Strict about its syntax (unlike Perl) Object oriented: Completely. Everything s an object. Does its own garbage collection Dynamically typed Strongly typed 7

8 Batteries included Clean language Modular extensions import re fx_regexp = re.compile('^f.*x$') fx_hits = fx_regexp.search(line) if fx_hits: 8

9 Batteries included numbers unicodedata calendar keyword json quopri math zlib optparse mimetypes locale re atexit crypt socket > 200 standard modules webbrowser imaplib sys random xml base64 os logging sched tempfile ssl datetime formatter pydoc getopt httplib urlparse pickle 9

10 More batteries NumPy SciPy Numerical Python Scientific Python Astronomy A.I. Biology Dynamical systems Economics Electromagnetics Geology Molecular modelling Signal processing Symbolic maths 10

11 Yet more batteries Python Package Index > 15,000 extra modules artistic communications database desktop documentation education games home internet multimedia office printing religion science security sociology system terminals text utilities 11

12 Ubiquity The capacity of being everywhere or in all places at the same time. O.E.D. 12

13 Ubiquity The capacity of being everywhere or in all places at the same time. Now! 13

14 Ubiquity Operating systems The capacity of being everywhere or in all places at the same time. Types of application Disciplines People 14

15 Operating Systems Unix Linux, MacOS X, BSD, AIX, Solaris, Irix, MS Windows DOS, CE, 2K, ME, NT, XP, Vista, 7. Others VMS, zos, OS/2, OS/400, BeOS, ipod, Palm, QNX, 15

16 Python Interpreted language Cross-platform (Unix/Linux, Windows, Mac OS X, etc) Strict about its syntax (unlike Perl) Object oriented: Completely. Everything s an object. Does its own garbage collection Dynamically typed Strongly typed 16

17 Implementations CPython IronPython Jython Stackless Unix.NET Java Multi-threaded 17

18 Applications Network services Web applications Graphical applications Command line applications Instrumentation control Embedded systems 18

19 Network services EVE Online MMORPG 300,000+ players Stackless Python 19

20 Web applications Django Turbogears Zope (Plone) 20

21 Web applications 21

22 Web applications 22

23 Graphical applications 23

24 GUI builders Java Python C++ Tk 24

25 Command line #!/usr/bin/python Scripts in /usr/bin 7% Ubuntu 1% OpenSUSE /usr/bin/command-not-found 25

26 Instrument control Serial port PyVISA Virtual Instrument Software Architecture Institute for Personal Robots in Education 26

27 Embedded systems IEEE based, auto-forming, multi-hop, instant-on, mesh network stack combined with an embedded Python interpreter for running application code. 27

28 Disciplines Artistic Pharmaceuticals Ship building Space travel 28

29 Academic disciplines Astronomy Bioinformatics Chemistry Zoology 29

30 Academic disciplines not in the sciences 30

31 in Cambridge Smooth Particle Hydrodynamics Basics of programming in Python Python Bioinformatics Crystallography Compression algorithms Dimensional quantities Astronomy Biochemistry CIMR Physics 31

32 Ubiquity The capacity of being everywhere or in all places at the same time. O.E.D. 32

33 But why? modules continuous development Immediate gratification Small scripts Fully featured Major projects 33

34 But why? modules continuous development Immediate return on investment Good return on investment 34

35 So what? + = + + =? 35

36 So what? modules Immediate return on investment Novel academic research possible Powerful admin-y scripts are easy 36

37 So what? modules Easy to get started Happy academics possible Happy I.T. staff possible 37

38 So what? modules A few remarkable results possible Good return on investment 38

39 Integration with existing code C, C++ Fortran Java.NET SWIG f2py Jython IronPython Python 39

40 So what should we do? Learn Python Encourage Python Encourage programming 40

41 #include <stdio.h> int main() { int rc; rc = printf("hello, world!\n"); if (rc!= 14) { perror("failed to print"); return(1); } return(0); } 41

42 print ('Hello, world!') 42

43 #include <stdio.h> int main() { printf("hello, world!\n"); return(0); } 43

44 try: print ('Hello, world!') except: pass 44

45 Python: Ubiquitous Good place to start Good return on investment 45

46 Python Two major versions in use: 2.x (2.7.2) and 3.x (3.2.1) Interpreted language Cross-platform (Unix/Linux, Windows, Mac OS X, etc) Strict about its syntax (unlike Perl) Object oriented: Completely. Everything s an object. Does its own garbage collection Dynamically typed Strongly typed 46

47 Books on Python 2 Dive Into Python Mark Pilgrim Apress ISBN: Best book on Python your presenter has found. (It was written for Python 2.3, though. Luckily, Python 2.4, 2.5 and 2.6 are very similar to Python 2.3.) Python Programming: An Introduction to Computer Science First Edition Superb introduction to John M. Zelle computer programming, Franklin, Beedle & Associates,Inc. using Python as a first ISBN: language (which also makes it a good introduction to Python). Official Python documentation: 47

48 Books on Python 3 Dive Into Python 3 Mark Pilgrim Apress ISBN: Python Programming: An Introduction to Computer Science Second Edition Superb introduction to John M. Zelle computer programming, Franklin, Beedle & Associates,Inc. using Python as a first ISBN: language (which also makes it a good introduction to Python). Official Python 3 documentation: 48

49 University of Cambridge Computing Service Python course notes are usually to be found at: 49

50 Questions? 50