Python Tutorial 1

1
Python Tutorial 1
??? Yu-Tsao Hsing

• Laboratory for Reliable Computing
• Department of Electrical Engineering
• National Tsing Hua University
• Hsinchu, Taiwan

2
Who am I ?

• Yu-Tsao Hsing (???)
• Email ythsing_at_larc.ee.nthu.edu.tw
• http//larc.ee.nthu.edu.tw/ythsing
• ?? H01

3
Reference

• Python ?? (Learning Python), Mark Lutz David
  Ascber, OREILLY??, ISBN957-8247-35-4
• ??Python, ???, ????, ISBN957-466-280-2
• Python ????, Guido van Rossum, ????http//larc.ee
  .nthu.edu.tw/jcyeh/python/cdoc/tut/tut.html

4
Procedure

• 7/14 Python Tutorial (1) PM 7001000
• 1. Introduction
• 2. How to start ?
• 3. Embedded object types
• 7/21 Python Tutorial (2) PM 100400
• 4. Control structure
• 5. Function

5
Procedure (cont.)

• 7/28 Python Tutorial (3) PM 100400
• 6. Modules
• 7. Packages
• 8. Basic I/O
• 8/4 Python Tutorial (4) PM 100400
• 9. Exceptions
• 10. Classes

6
1. Introduction
7
Python

• 1991 ?? Guido van Rossum ?????????????
• ??? Zope ????? PythonLabs ?????
• ?? Python ? C ?????????

• ???? Scripting Language
• ? Java ?????? Jython ????,??? .NET ??

8
Why we need learning python?

• ????? (Object Oriented)
• ??????? (Interpreted, Interactive)
• ??? (Cross Platform)
• ???? (Easy Learning)
• ?????? (Clear Syntax and Structure)
• ????? (Extended and Embedded)
• ???? (Open Source)

9
Applications

• Red Hat Linux ??????

10
Applications

• ???? mailman ??

11
Graphic User Interface
12
Resources Online

• Python Language Website
• http//www.python.org/
• ???????????...
• Dive Into Python
• http//diveintopython.net/
• ??????...
• Zope Python User Group
• http//zpug.org/
• ? WiKi ??????...
• JPython Website
• http//jpython.sourceforge.net/
• Java ?????????...

• Starship Python
• http//starship.python.net/
• ??????...
• Non-Programmers Tutorial For Python
• http//www.honors.montana.edu/
• jjc/easytut/easytut/easytut.html
• Python FAQ
• http//www.python.org/doc/FAQ.html
• ????????????...
• ActiveState
• http//www.activestate.com/
• ?? Python?Perl?Tcl ???...

13
2. How to Start
14
Some Rules

• gtgtgt ???python?????
• ???Unix (or PC)???
• python???????
• ?????
• .py python??????
• .pyc ???????python?????

15
Install

• Unix
• ????
• PC
• http//www.python.org/ftp/python/2.3.4/Python-2.3.
  4.exe
• ??????????
• ?????

16
Hello Python !

• In Unix
• python
• gtgtgt print Hello python !
• Hello python !
• ??Ctrl D????
• In PC
• ??gtPython 2.3gt IDLE(python GUI)
• gtgtgt print Hello python !
• Hello python !
• ????????????

17
????python???

• ????????????LaRC.py
• ????????? python??
• python LaRC.py
• ???(Unix?)?????????
• !/usr/local/bin/python
• ???
• chmod X LaRC.py
• LaRC.py

18
??????

• Python???????????
• ???dir()?????????????
• gtgtgt x 1
• gtgtgt y LaRC
• gtgtgt dir( )
• __builtins__, __doc__, __name__, x, y
  
• gtgtgt dir(x)
• ??????????????

19
3. Embedded Object Type
20
Python?????

• Python???????, ???????(Module), ??(Statement),
  ???(Object)
• ?????????
• ?????????
• ????????????
• Everything in python is object !!

21
??????
???? ???? ??
?? Number 3.1415, 1234, 999L, 34j
?? String LaRC, NTHUs
?? List 1, 2, three, 4
?? Dictionary foodspam, tasteyum
Tuple Tuple (1, LaRC, 4, U)
?? File text open(eggs, r).read()
22
3.1 Number
23
Number-Introduction

• ??, and ??????
• ?C????, ????and?????????
• ???????

?? ??
1234, -24, 0 ????
999999999999L ???
1.23, 3.14e-10, 4E210, 4.0e210 ???
0177, 0x9ff 8???16????
34j, 3.04.0j, 3J ????
24
Number-??????

• ????????
• ????10???????
• ?????or??????????
• ??????
• ?? in Python long integer in C (32 bits)
• ??? in Python Double float in C
• ????L (or l), ?????????
• 16???8????
• 8?????0 ???????0, ????
• 16?????0x (or 0X)
• ??
• ??????j (or J)??
• ??????????

25
Number-????????(1/3)

• ???Python??????
• ???????????
• ??????????????????

??? ??
x or y, lambda args expression or?????, ????????
x and y and?????
not x ???????
lt, lt, gt, gt, , ltgt, ! is, is not in, not in ????? ???? ???????
26
Number-????????(2/3)
??? ??
x y or ?????
x y xor?????
x y and?????
x ltlt y, x gtgt y ?x??or????y???
x y, x - y ??, ??
x y, x / y, x y ??, ??, ????
-x, x, x ??, ??, ???????
xi, xij, x.y, x() ??, ??, ??????, ????
(), , , Tuple, ??, ??, ?????
27
Number-????????(3/3)

• ????
• ?????????????Q_Q
• ???()???
• ??????????????
• ?????????????
• ?????python?????????????
• Python????????????????
• ?? lt ??? lt ??? lt ??
• ?????

28
Number-????(1/3)

• ???? ?????????
• Python
• gtgtgt a 3 ????lt????
• gtgtgt b 4
• gtgtgt b / 2 a ?? ((4/2)3)
• 5
• gtgtgt b / (2.0 a) ?? (4/(2.03))
• 0.8
• ????
• ??2.0a, ??2.0, ?a?3gt3.0, ??5.0
• ??b/5.0, ??5.0, ?b?4gt4.0, ??0.8
• If ?? 2 ???,?4/5???0

29
Number-????(2/3)

• ???? ??C??, ?????
• For ????, ???????
• gtgtgt x 1 001
• gtgtgt x ltlt 2 100, ??????
• 4
• gtgtgt x 2 011, 001 OR 010
• 3
• ??? ??????
• ??, ???, ???!!! (?????????)
• gtgtgt 9999999999999999999999999999999 1
• OverflowError integer literal too large
• gtgtgt 9999999999999999999999999999999L 1
• 10000000000000000000000000000000

30
Number-????(3/3)

• ?? ????
• gtgtgt 1j 1J
• (-1 0j)
• gtgtgt 2 1j 3
• (23j)
• gtgtgt (2 1j) 3
• (63j)
• ?????
• ????math??????
• gtgtgt import math
  ??C??includeltxxx.hgt
• gtgtgt math.pi p
• 3.14159265359
• gtgtgt abs(-42), 24, pow(2,4)
• (42, 16, 16)

31
3.2 String
32
String-Introduction

• ?????
• Immutable sequence ??????
• ???????????
• ???Lists????
• ???????
• S1 ???
• S2 spams ???
• Block ?????
• ??? or ??? ?? ????? !!
• ?????????????????

33
String-???????

• ????
• S1 S2 ??
• S2 3 ????
• for x in S2 ???????
• m in S2 ????
• ?????????
• S2 i ????
• S2 i j ????
• len(S2) ????
• ?????????
• a s parrot dead ???????

34
String-????(1/2)

• ??????
• gtgtgt len ( LaRC )
• 4
• ???????
• gtgtgt LaRC EE
• LaRCEE
• ?????? LaRC LaRC LaRC
• gtgtgt LaRC 3
• LaRCLaRCLaRC
• ????? !!
• Python ??????
• LaRC 3 ???????

35
String-????(2/2)

• ???????????????
• gtgtgt mylab LaRC
• gtgtgt R in mylab
• 1 means
  true
• gtgtgt for letter in mylab ???????
• print letter
• L
  ??print????
• a
• R
• C
• We will discuss the detail in next week

36
String-????????(1/3)

• ????C??, ?? 0 n-1
• ?????????? -n -1
• Offset_p Offset_n n
• gtgtgt mylab LaRC
• gtgtgt mylab0, mylab-2 ??????
• ( L , R ) tuple
• gtgtgt mylab13 ????
• aR
• ????? (lower buond), (upper bound)
• gtgtgtmylab1, mylab-1 ????
• ( aRC , LaR ) tuple

37
String-????????(2/3)
0
1
2
-2
-1
I
H
a
v
e
a
D
r
e
a
m

• ???? (Si)
• ??????????
• ???????????????
• S-2 Slen(S)-2
• ???? (Sij)
• ????????????????
• ?????????0?len(S)
• S-1 ??????????????????

38
String-????????(3/3)

• ???????1?????
• cat echo.py
• Import sys
  ??C??includeltxxx.hgt
• Print sys.argv
• Print sys.argv1
• python echo.py a b c
• echo.py , a , b , c
• a , b , c
• ???????2?????????????
• gtgtgt LaRC Lab for Reliable Computing\n
• gtgtgt LaRC-1
• Lab for Reliable Computing

39
String-????

• ?????!
• gtgtgt mylab LaRC
• gtgtgt mylab3 K
• Traceback (most recent call last)
• File ltpyshell9gt, line 1, in toplevel-
• TypeError object doesnt support item assignment
• ???, ?? !!
• ???????????
• gtgtgt mylab mylab-1 K!
• gtgtgt mylab
• LaRK!
• gtgtgt mylab mylab4 is a bird
  mylab-1
• LaRK is a bird!

40
String-????(1/3)

• gtgtgt That is d s! (1, bird )
  ??C?sprintf
• That is 1 bird!
  tuple
• ????? !!
• ??????

s ?? X 16????(??)
c ?? e ???????(??)
d 10???? E ???????(??)
i ?? f ???????
u ???? g ??????(??)
o 8???? G ??????(??)
x 16???? ????
41
String-????(2/3)

• gtgtgt Mylab LaRC
• gtgtgt I am in s now! Mylab
• I am in LaRC now!
• gtgtgt d s d ? (1, , 1)
• 1 1 ?
• gtgtgt s - s - s (33, 3.1415926, 1, 2, 3)
• 33 3.1415926 1, 2, 3
• s??????????????????
• ????????_at_O_at_
• ?????????????
• gtgtgtI 3.1415926
• gtgtgtI s I
• gtgtgtI
• 3.1415926
• ??????????
• ???????????

42
????-???????

• Python????????-string
• gtgtgtimport string
• gtgtgtS immediaTely
• gtgtgtstring.upper(S)
  ?????
• IMMEDIATELY
• gtgtgtstring.lower(S)
  ?????
• immediately
• gtgtgtstring.find(S, mm)
  ??mm?string????
• 1
• gtgtgtstring.atoi(151), 151
  ?????????????
• ( 151, 151 )
• gtgtgt LaRC 151, string.atoi(151) 2
• (LaRC151, 153)
• gtgtgtstring.join(string.split(S, mm), ll)
  ?mm??, ??ll????
• illediaTely
• ?????Python?Help?

43
String-????(3/3)

• ????
• gtgtgtSARS We are the World
• gtgtgtSARS
• WearetheWorld
• gtgtgtBig Oh, what is this ?
• It is too big !!!
• gtgtgtBig
• Oh, what is this ? \n It is too big !!!

\newline ??? \n ????
\\ ??? \v ????
\ ??? \t ????
\ ??? \r ????
\a ?? \f ??
\b ???? \0XX 8????
\000 ??? \xXX 16????
44
???????-?????????

• ??python???????????, ?????????, ??????????,
  ???????????, ?????
• ????????????
• Python?????????????????
• ?????????
• ?????????, ????, ??
• ?????key?????????
• ??, ??, ????????????_at_O_at_
• ???????, ?????????
• ???????
• ?????? (shared object reference)

45
3.3 List
46
List-Introduction

• ?????????
• ??????
• ???????(??, ??, ????)
• ????????
• ????????, ?????
• ?????, ????????gt?????,??
• ????, ??????
• ??????, ?????
• ????????????????
• ?????????
• ??????????????
• ????????????????
• ???????, ??????????????

47
List-??????

• ??????, ????????????
• ??? ?????????
• ?????C?????
• ????????
• ??????(??)
• ???, ?????????, ???????
• ?????????????
• ?????????????or????
• ?????????????
• ????copy????
• ????????????????

48
List-???????(1/2)

• ????
• L1
  ???
• L2 0, 1, 2, 3
  4??????
• L3 abc, def, ghi ????
• len (L2)
  ??
• L1 L2 ??
• L2 3
  ????
• For x in L2
  ????
• 3 in L2
  ????????
• ??????????
• L2 i , L3 i j
  ?????
• L2 i j
  ????

49
List-???????(2/2)

• ?????? lt??????
• L2.append(4) ????
• L2.sort( ) ??
• L2.index(1) ??
• L2.reverse( ) ??
• del L2 k ????
• L2 i j
• L2 i 1 ?????
• L2 i j 4, 5, 6 ????
• range(4), xrange(0, 4) ??????? / tuple

50
List-????(1/2)

• ??
• gtgtgt len( 1, 2, 3 )
• 3
• ??
• gtgtgt 1, 2, 3 4, 5, 6
• 1, 2, 3, 4, 5, 6
• ????
• gtgtgt Oh 4
• Oh, Oh, Oh, Oh
  ?????
• ??????
• gtgtgt for x in 1, 2
• print x
• 1
• 2

51
List-????(2/2)

• ??, ??????
• ??????? ???????
• ??????? ???????
• ????????????????Q_Q
• ????
• Ans. ?????
• ?????, ??
• ?????, ??list()
• gtgtgt 1, 2 34 ?? 1,2
  34
• 1, 2 34
• gtgtgt 1, 2 list( 34 ) ?? 1, 2
  3, 4
• 1, 2, 3, 4

52
List-??????????

• ??????????
• gtgtgt mylab larc, Larc?, LaRC!
• gtgtgt mylab 2
• LaRC!
• gtgtgt mylab -2
• Larc?
• gtgtgt mylab 1 ??????????
• Larc?, LaRC!
• ???????, ??????????

53
List ??????(1/3)

• ???????????????
• gtgtgt mylab larc, Larc?, LaRC!
• gtgtgt mylab 1 is ????????
• gtgtgt mylab
• larc, is, LaRC!
• ?????? ???????????????
• gtgtgt mylab 0 2 Im, a
• gtgtgt mylab ?0,1??????
• Im, a, LaRC!
• ??????????
• gtgtgt mylab 1 2 student, in
• gtgtgt mylab
• Im, student, in, LaRC!

54
List-??????(2/3)

• ??????
• ????(qualification) (.)
• ?????????
• ????
• ?????, ??????????, ????
• gtgtgt mylab.append( nthu )
• gtgtgt mylab
• Im, student, in, LaRC!, nthu
• ???? mylab mylab nthu
• ??? mylablen(mylab) nthu
• ??? mylablen(mylab) nthu
• ??????
• ???????, ???????????
• ??, ??????

55
List-??????(3/3)

• ??
• ??????, ????????
• gtgtgt mylab.sort( )
  ??ASCII???
• gtgtgt mylab
• Im, LaRC!, in, nthu, student
• ??
• gtgtgt del mylab-1 ??????
• gtgtgt mylab
• Im, LaRC!, in, nthu
• gtgtgt del mylab-1 ??????
• gtgtgt mylab
  ??mylab-1
• nthu

56
3.4 Dictionary
57
Dictionary-Introduction

• ?key??, ?????
• ?????(associative array), ??(hash)
• Key, ?????????(value)???????
• ?????????, ?????key not ???
• ??????, ????????
• ??????????????
• Key??????????, ??????
• ??????value?, ?????
• ????, ???, ??????
• ??????, ???????? (????)
• ?????
• ????????(??), ?????????
• ??????, ???????????
• ???????(???)
• ????????????lt????????
• ???(Hash Table)

58
Dictionary-???????

• ????
• D1
  ???
• D2 LaRC1, NTHU2
  ?????????
• D3 TWLaRC1, NTHU2 ????
• D2NTHU, D3TWLaRC ?key??
• D2.has_key(NTHU)
  ??????
• D2.keys()
  key??
• D2.values()
  ?????????
• len(D2)
  ????
• ??????
• D2key new
  ??/??????
• Del D2key
  ??

59
Dictionary-????

• ??key???
• gtgtgt D2 LaRC1, NTHU2, TW3
• gtgtgt D2NTHU
• 2
• ????????
• gtgtgt len(D2)
• 3
• Key?????
• gtgtgt D2.hes_key(TW)
• 1
• ??key (??????)
• ?????????, ???
• gtgtgt D2.keys()
• LaRC, NTHU, TW

60
Dictionary-??????

• ????key????, ????key??????
• ?????
• gtgtgt D2NTHU EE, CS
• gtgtgt D2
• LaRC1, NTHUEE, CS, TW3
• ?????
• gtgtgt del D2TW
• gtgtgt D2
• LaRC1, NTHUEE, CS
• ?????
• gtgtgt D28 floor
  key???????
• gtgtgt D2
• 8Floor, LaRC1, NTHUEE, CS

61
Dictionary-?????

• gtgtgt table Python Guido van Rossum,
• Perl Larry Wall,
• Tcl John Ousterhout
• gtgtgt language Python
• gtgtgt creator tablelanguage
• gtgtgt creator
• Guido van Rossum
• gtgtgt for lang in table.keys()
• print lang, \t, tablelang
• Perl Larry Wall
• Tcl John Ousterhout
• Python Guido van Rossum
• ????????, ??for??????keys()?????

62
3.5 Tuple, File
63
Tuple-Introduction

• ??????
• ??---????
• ???????????
• ????????or????
• ????????
• ????????
• ?????????????????
• ????????????????
• ???function?????
• ??????????

64
Tuple-??tuple??

• ( )
  ?tuple
• T1 (0, )
  1????tuple(??????)
• T2 (0, 1, 2, 3) 4????tuple
• T3 0, 1, 2, 3
  4????tuple(?????)
• T4 (abc, (def, ghi)) ??tuples
• T1 i , T3 i j ?????
• T1 ij , len(t1) ????, ??
• T1 T2 ??
• T2 3 ????
• for x in T2 ????
• 3 in T2 ????

65
File-Introduction

• ???????
• ???????????
• ?????C???stdio?
• Output open(/tree/temp.dat, w)
• Input open(data.dat, r)
• ??
• r????
• w???????
• a??????

66
File-????????

• S input.read( ) ??????
• S input.read(N) ??N????
• S input.readline() ?????
• L input.readlines() ????????????
• Output.write(S) ???????
• Output.writelines(L) ??????????
• Output.close() ????
• gtgtgt myfile open(myfile.txt, w) ?????
• gtgtgt myfile.write(hello text file\n) ?????
• gtgtgt myfile.close()
• gtgtgt myfile open(myfile.txt, r) ?????
• gtgtgt myfile.readline()
  ?????
• hello text file\n
• gtgtgt myfile.readline()
  ??? ????

67
3.6 ??
68
???????(1/3)

• ?????

??
???
??
??
??
???
????
???
??
??
??
???
??
??
Tuple
69
???????(2/3)

• ??????
• Assignment manipulates references
• x y does not make a copy of y
• x y makes x reference the object y references
• ????, ????????
• Example
• gtgtgt a 1, 2, 3
• gtgtgt b a
• gtgtgt a.append(4)
• gtgtgt print b
• 1, 2, 3, 4

70
???????1
a 1, 2, 3
b a
a
1
2
3
4
a.append(4)
b
71
???????2
a 1
a
1
b a
b
new int object created by add operator (11)
2
a
a a1
old reference deleted by assignment (a...)
1
b
72
???????(3/3)

• gtgtgt L1 1, 2
• gtgtgt L2 1, 2
• gtgtgt L1 L2, L1 is L2
• (1, 0)
• ??
• ??????????
• is ????????????
• ???
• ? xx, 1
• ? , , , 0.0, None ??C???NULL
• ??
• ??????????
• ??????, ??????????
• ???Tuple?????????
• ??????????

73
?????(1/2)

• ????()?????
• ????
• gtgtgt L 1, 2, 3
• gtgtgt M X, L, Y M X, L , Y
  
• gtgtgt M
• X, 1, 2, 3, Y
• gtgtgt L1 0
• gtgtgt M
• X, 1, 0, 3, Y
• ??????
• ?????????????
• gtgtgt L 1 L.append(L)
• gtgtgt L
• 1,

74
?????(2/2)

• ??????
• ????, ?????????????
• gtgtgt L 4, 5, 6
• gtgtgt X L 3
• gtgtgt Y L 3
  L L L L, L, L
• gtgtgt X
• 4, 5, 6, 4, 5, 6, 4, 5, 6
• gtgtgt Y
• 4, 5, 6, 4, 5, 6, 4, 5, 6
• gtgtgt L1 0
• gtgtgt X
• 4, 5, 6, 4, 5, 6, 4, 5, 6
• gtgtgt Y
• 4, 0, 6, 4, 0, 6, 4, 0, 6

75
Summary

• ????
• Python???
• ????python
• Unix
• PC
• ??????
• ??, ??, ??, ??, tuple, ??
• Whats in next week ?
• ???????
• ??
• ???
• ?????HW???