Introduction to Python for IBM i

Transcription

1 Introduction to Python for IBM i Mike Pavlak IT Strategist mike.pavlak@freschesolutions.com

2 Agenda A little about Python Why use Python How to install/determine if installed IDE Syntax 101 Variables Strings Functions Database Toolkit 2

3 Acknowledgements Kevin Adler Tony Cairns Jesse Gorzinski Google Memegenerator Corn chips and salsa Parrots And, of course, spam 3

4 A little about Python

5 What is it, really? General purpose language Easy to get started Simple syntax Great for integrations (glue between systems) Access to C and other APIs Infrastructure first, but applications, too 5

6 Historically Python was conceptualized by Guido Van Rossum in the late 1980 s Rossum published the first version of Python code (0.9.0) in February of 1991 at the CWI(Centrum Wiskunde & Informatica) in the Netherlands, Amsterdam Python is derived from the ABC programming language, which is a general purpose language that was also developed at CWI. Rossum chose the name Python since he was a fan of Monty Python s Flying Circus. Python is now maintained by a core development team at the institute, although Rossum still holds a vital role in directing its progress and as leading commitor. 6

7 Why Python?

8 / Data survey 40,000 developers, worldwide 11

9 Got Python?

10 Details at Developerworks The sun is setting on OPS! munity/wikis/home?lang=en#!/wiki/ibm%20i %20Technology%20Updates/page/Open%20S ource%20technologies 13

11 Need licensed program 5733OPS Base and option 2 or 4 14

12 Times change That was then this is now 15

13 Leverage RPM s Use ACS to do the heavy lifting! But fire up SSH first. 16

14 Insert RPM stuff here Use ACS to do the heavy lifting! 17

15 Select system and credentials 18

16 19

17 20

18 Now install Python3 21

19 Info command 22

20 Confirm Is this ok [y/n] 23

21 Watch the installation until complete 25

22 Looking back at ACS in the installed tab 26

23 Python in action Command line via green screen 27

24 Hello World 28

25 Most prefer SSH Command line via SSH terminal Recommended strongly by Jesse! 29

26 Shell available in ACS (shortcut to ) Encrypted BASH, etc. Linux alignment 30

27 Hello World, again 31

28 IDE

29 Zend Studio No, you don t need to buy Zend Studio Use Orion, etc. But if you have Studio or RDi Consider something from Eclipse.org I grabbed PyDev 33

30 Eclipse 34

31 Download PyDev from Eclipse 35

32 Capture URL Help Install New Software Follow prompts 36

33 Editor for Eclipse Select what you like Click next 37

34 Confirm versions Click next again Then accept EULA 38

35 Watch the pretty status bar 39

36 Python in Eclipse (i.e. Zend Studio) I bet RDi works, too! 40

37 Alternatives to IBM i when learning What s that? The boss won t let you install Python on the IBM i? Consider repl.it 41

38 Desktop education at it s finest How about your PC? Head to Python.org site: Download Install Viola! 42

39 Python Script in IFS Create a file like Ex01hello.py Open the file Key up some code and click save Rinse, repeat 43

40 Python Syntax Fundamentals

41 How it is written Indentation means EVERYTHING Don t use tab 4 spaces No more, no less Mismatched indents can cause failures. Good luck finding No scope terminators like other languages Colon introduces start block, then indent Much more readable than other languages Get a good editor!!! 46

42 Indentation 47

43 Operators Similar to other C derivatives Comparison Assignment = Comparison == Inequality!= Less than < Greater than > Less than or equal to <= Greater than or equal to >= Mathematical Addition + Multiplication * Division / Floor division // Modulus % Exponentiation ** Booleans And Or Not 48

44 Syntax Variables

45 Data types yeah about that Int Integer of unlimited size Float System defined precision Complex Complex with real and imaginary parts Strings Sequences of character data Bool TRUE & FALSE 50

46 Variables on the fly Case sensitive camelcase Who are you? type() 51

47 Variables in a file 52

48 Data type? 53

49 Every variable is implemented as a class 54

50 And now for something completely different 55

51 It s OK Monty Python references are not only acceptable They are encouraged! Documentation is littered with references Examples are well covered 56

52 Back to variables Numbers 3 Data types Integer 1,2,42 Float Complex: <real> + <imaginary> (not used much ) 57

53 Strings Immutable objects, cannot change value Can reassign. (dynamic typing) Single or Double quotes, OK (even triple ) Index starts at 0 (of course ) 58

54 String formatting Interpolation, of sorts 59

55 Set Processing

56 Lists Ordered group, similar to array Different data types, ok Multi-dimensional (sub lists) Mutable (changeable) 61

57 Tuples Similar to lists Immutable (don t change once created) Use parenthesis instead of brackets 62

58 Dictionary Again, like lists but more like hash or PHP Assoc. Array Mutable Key value pairs 63

59 Control Structures

60 ifs 65

61 for loop 66

62 while loop 67

63 Functions

64 Built in functions About 68 Math Type Iterables Composite Classes Variables/Reference Scope Misc 69

65 Built in s are straight forward #rounding... valuein = 98.5 valueout = round(valuein) print("\n", valuein, " becomes ", valueout, " when rounded!\n") #set processing MySet1 = [23, 18, 14, 16, 21] minset = min(myset1) print("\nin the set ", MySet1, " the minimum value is ", minset) print(" while the maximum value is ", max(myset1)) #How about that object ID? print("\n the ID for the set above is ", id(myset1)) print("\n the ID for valuein above is ", id(valuein)) print("\n the ID for min above is ", id(minset)) 70

66 User Defined Functions 71

67 Functions with defaults 72

68 Functions with Keyword arguments 73

69 Command Line

70 Input from command line Talk to the script 75

71 Database

72 Locate the package or wheel 77

73 Install commands 78

74 Find the connector YMMV With wheels 79

75 Run the pip install pip == Python installer program 80

76 What version of the DB2 Extension? 81

77 Steps for simple database Access Import the class Connect (with or without options Open the cursor Set the SQL Read 82

78 Simple database access 83

79 Table info 84

80 IBM i Toolkit

81 A few ways to access toolkit Transition from Python2 to Python3 and RPM Broke a few things Under construction This will work 86

82 Toolkit Version IBM is maintaining version numbers # import itoolkit #Version? print("\nthe itoolkit version is: " + itoolkit. version + "\n") 87

83 CL Command import itoolkit as tkt import itoolkit.db2.idb2call as Db2tkt itool = tkt.itoolkit() print("\nthe itoolkit version is: " + tkt. version + "\n") itransport = Db2tkt.iDB2Call('PYUSER1', 'pyuser1') itool.add(tkt.icmd5250('dsplibl', 'dsplibl')) itool.call(itransport) # output commandoutput = itool.dict_out('dsplibl') if 'error' in commandoutput: print (commandoutput['error']) exit() else: print (commandoutput['dsplibl']) 88

84 Summary Why Python Lot s of libraries Make it easy to do stuff OPC / OPO Education 89

85 End the session 90

86

87 THANK YOU