Learn python

1. Programming at the speed of light Pythonism Kracekumar.R [email_address]

2. Agenda What is Python ???

3. Why Python ???

4. Syntax Walkthroughs

5. Linux and Python

6. What is Python ??? What is Python ???

7. Why Python ???

9. Linux and Python

10. History Created by Guido von Rossum in 1990 (BDFL)

11. named after Monty Python's Flying Circus

12. http://www.python.org/~guido/

13. Blog http://neopythonic.blogspot.com/

14. Now works for Google

15. What is Python ??? general-purpose high-level programming language, often used as a scripting language.

16. interpreted, interactive, object-oriented.

17. incorporates modules, exceptions, dynamic typing, very high level dynamic data types, and classes, automatic memory management.

18. remarkable power with very clear syntax.

19. has interfaces to many system calls and libraries, as well as to various window systems, and is extensible in C or C++.

20. What is Python ??? supports multiple programming paradigms (primarily object oriented, imperative, and functional)

21. portable: runs on many Unix variants, on the Mac, and on PCs under MS-DOS, Windows, Windows NT, OS/2, FreeBSD Solaris, OS/2, Amiga,AROS, AS/400, BeOS, OS/390, z/OS, Palm OS, QNX, VMS, Psion, Acorn RISC OS, VxWorks, PlayStation, Sharp Zaurus, Windows CE and even PocketPC !

22. What is Python ??? Developed and supported by a large team of volunteers - Python Software Foundation

23. Major implementations: CPython, Jython, Iron Python, PyPy CPython - implemented in C, the primary implementation

24. Jython - implemented for the JVM

25. Pypy - implemented in Python

26. IronPython - implemented in C#, allows python to use the .NET libraries

27. Why Python ??? What is Python ???

28. Why Python ???

30. Linux and Python

31. Why Python ??? Readability, maintainability, very clear readable syntax

32. Fast development and all just works the first time...

33. very high level dynamic data types

34. Dynamic typing and automatic memory management

35. Free and open source Implemented under an open source license. Freely usable and distributable, even for commercial use. Simplicity , Great first language

36. Availability (cross-platform)

37. Interactivity (interpreted language)

38. Why Python ??? GUI support – GUIs typically developed with Tk

39. Strong introspection capabilities

40. Intuitive object orientation

41. Natural expression of procedural code

42. Full modularity, supporting hierarchical packages

43. Exceptionbased error handling

44. The ability to be embedded within applications as a scripting interface

45. Scalable – can play nicely with other languages

46. Batteries Included The Python standard library is very extensive regular expressions, codecs

47. date and time, collections, threads and mutexs

48. OS and shell level functions (mv, rm, ls)

49. Support for SQLite and Berkley databases

50. zlib, gzip, bz2, tarfile, csv, xml, md5, sha

51. logging, subprocess, email, json

52. httplib, imaplib, nntplib, smtplib

53. and much, much more ...

54. Python Libraries Biopython - Bioinformatics

55. SciPy - Linear algebra, signal processing

56. NumPy - Fast compact multidimensional arrays

57. PyGame - Game Development

58. Visual Python - real-time 3D output

59. Django - High-level python Web framework

60. and much more ...

61. E.g. Projects with Python Websites: Google, YouTube, Yahoo Groups & Maps, CIA.gov Appengine: http://code.google.com/appengine/

62. ” Google: Python has been an important part of Google since the beginning.”, Peter Norvig.

63. Python application servers and Python scripting to create the web UI for BigTable (their database project) Systems: NASA, LALN, CERN, Rackspace Nasa Nebula http://nebula.nasa.gov/about Games: Civilization 4, Quark (Quake Army Knife)

64. Mobile phones: Nokia S60 (Symbian), PythonCE

65. P2P: BitTorrent

66. Cont . . . Maya, a powerful integrated 3D modeling and animation system, provides a Python scripting API.

67. EVE Online, a Massively Multi player Online Game (MMOG), makes extensive use of Python.

68. iRobot uses Python to develop commercial robotic devices.

69. What can you do with Python Systems Programming

70. GUI

71. Internet Scripting

72. Database Programming

73. Numeric and Scientific Programming

74. Natural language analysis

75. What people say about Python ? I can remember many Python idioms because they're simpler. That's one more reason I program faster [in Python]. I still have to look up how to open a file every time I do it in Java. In fact, most things in Java require me to look something up. --Bruce Eckel

76. Cont . . . Python ... is compact -- you can hold its entire feature set (and at least a concept index of its libraries) in your head. -- Eric S. Raymond

77. Syntax Walkthroughs What is Python ???

78. Why Python ???

80. Linux and Python

81. Talk is cheap. Show me the code. Linus Torvaldus

82. Hello World Python 2.6 Python 3.0 print (“Hello World”) print “Hello World”

83. Starting python Open terminal and Enter python and hit enter Something like this kracekumar@kracekumar-laptop:~$ python Python 2.6.4 (r264:75706, Dec 7 2009, 18:45:15) [GCC 4.4.1] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>>

84. Interactive shell >>> 2+3

86. >>> 2*3

88. >>> 2/3

90. >>> 2//3

92. Interactive Shell cont . . . >>> 2.0/3.0

93. 0.66666666666666663

94. >>> 2.0/3

95. 0.66666666666666663

96. >>> 2/3.0

97. 0.66666666666666663

98. >>> 2-3

99. -1

100. Interactive shell Cont . . . >>> complex(3,4)

101. (3+4j)

102. >>> 5+4j+5+6j

103. (10+10j)

104. >>> pow(4,5)

105. 1024

106. >>> 4**5

107. 1024

108. Math More >>> 3%4

109. 3

110. >>> long(34.999999)

111. 34L

112. >>> int(34.9999)

113. 34

114. >>> str(5)

115. '5'

116. Still more Interactive shell >>> chr(45)

117. '-'

118. >>> ord('a')

119. 97 You can do more in interactive shell ,But you might be bored,so Lets start writing small scripts

120. First program Open first.py

121. Run python first.py ,Your program will be interpreted and python will produce .pyc in memory .

122. .pyc =>python compiled

123. Duck typed programming language

124. Interactive Shell (Revisited) >>> b='0x123'

125. >>> type(b)

126. <type 'str'>

127. >>> b=23

128. >>> type(b)

129. <type 'int'>

130. >>> c=32L

131. >>> type(c)

132. <type 'long'>

133. Cont . . . >>> c=2**890

134. >>> c

135. 8254602048994769474255309139320571976856989469314398783249386078541779727448825929287769623244643560854287421769642635607536680617229461519539671538483430889193541937484454440136429963694163141453503639190799818814812942074243152169349951543234944945149040326527156224L

136. >>> len(str(c))

137. 268

138. Str() =>Find string length

139. String >>> name='krace'

140. >>> name1="krace"

141. >>> name2="""krace"""

142. >>> name3='''krace'''

143. >>> name

144. 'krace'

145. >>> name1

146. 'krace'

147. >>> name2

148. 'krace'

149. >>> name3

150. 'krace'

151. Importing in built modules Open try_import .py

152. Strings

153. >>> name="kracekumar"

154. >>> name[1:]

155. 'racekumar'

156. >>> name[:1]

157. 'k'

158. >>> name[:5]

159. 'krace'

160. >>> name[:-5]

161. 'krace'

162. Strings are immutable >>> name[0]="a"

163. Traceback (most recent call last):

164. File "<stdin>", line 1, in <module>

165. TypeError: 'str' object does not support item assignment

166. >>> name

167. 'kracekumar'

168. >>> name="K"+name[1:]

169. >>> name

170. 'Kracekumar'

171. Above is a small hack to change the first character value in the name

172. Slicing >>> name[1:5]

173. 'race'

174. >>> name + " likes linux " #concatenation

175. 'Kracekumar likes linux '

176. >>> name.startswith('k')

177. False

178. >>> name.upper()

179. 'KRACEKUMAR'

180. Python introspection Python introspection lets you to find all builtin functions,classes etc. . .

181. >>> dir()

182. ['__builtins__', '__doc__', '__name__', '__package__', 'a', 'b', 'c', 'name', 'name1', 'name2', 'name3', 'sys']

183. dir(anyname) =>will yield all the supported functions.

184. In Built help help(anyname)

185. >>> help(a) no Python documentation found for '123' #here no documentation is available so you won't find help(sys) Find the magic here :)

186. Data structure 3 in built data structure

187. List => a=[1,”linux”,2,”Free Bsd”]

188. Tuple => b=(1,”apple”,mango)#mango is not quoted because here it refers variable

189. Dictionary =>dict={”name”:”kracekumar”,”email”:” [email_address] ”,”coll”:”Amrita”}

190. Don't worry guys you have array but i will introduce later

191. Data structure >>> a

192. [1, 'linux', 2, 'Free Bsd']

193. >>> b

194. (1, 'apple', 'mango')

195. >>> dict

196. {'coll': 'Amrita', 'name': 'kracekumar', 'email': '[email protected]'}

197. List is not linked list here

198. You can have string ,int,float in list,tuple,dictionary

199. Data structure in python >>> type(a)

200. <type 'list'>

201. >>> type(b)

202. <type 'tuple'>

203. >>> type(dict)

204. <type 'dict'>

205. Tuple is immutable

206. Cont . . . >>> a[1]

207. 'linux'

208. >>> a[1]="UBuntu"

209. >>> a[1]

210. 'UBuntu'

211. >>> a

212. [1, 'UBuntu', 2, 'Free Bsd']

213. Cont . . . >>> b[1]

214. 'apple'

215. >>> b[1]="pine apple"

216. Traceback (most recent call last):

217. File "<stdin>", line 1, in <module>

218. TypeError: 'tuple' object does not support item assignment

219. >>> b

220. (1, 'apple', 'mango')

221. Dictionary >>> dict

222. {'coll': 'Amrita', 'name': 'kracekumar', 'email': '[email protected] '}

223. coll =>is key and 'Amrita' =>value

224. All key should be unique

225. >>> dict['coll']="ASE"

226. >>> print dict

227. {'coll': 'ASE', 'name': 'kracekumar', 'email': '[email protected]'}

228. >>> dir(dict)

229. Dictionary functions dir() and help() will help you to know more about list tuple

230. dir(dict) Try has_key()

231. Pop()

232. Items()

233. Slicing holds for list and tuples

234. Control Flow if guess == number: #do something elif guess < number: #do something else else : #do something else while True : #do something #break when done break else : #do something when the loop ends for i in range( 1 , 5 ): print (i) else : print ( 'The for loop is over' ) #1,2,3,4 for i in range( 1 , 5 , 2 ): print (i) else : print ( 'The for loop is over' ) #1,3

235. Program Wap to find a no is prime or not

236. List comprehension

237. E.g >>> x=[y for y in range(0,20) if y%2 == 0]

238. >>> x

239. [0, 2, 4, 6, 8, 10, 12, 14, 16, 18]

240. Alternate way to do

241. Open list_comp.py

242. Dictionaries,list,tuple can be nested

243. Functions Order is important unless using the name Default arguments are supported def sayHello (): print ( 'Hello World!' ) def foo (name, age, address) : pass foo( 'Tim' , address= 'Home' , age= 36 ) def greet (name= 'World' )

244. Functions Variable length args acceptable as a list or dict def total (initial= 5 , *numbers, **keywords): count = initial for number in numbers: count += number for key in keywords: count += keywords[key] return count print (total( 10 , 1 , 2 , 3 , vegetables= 50 , fruits= 100 ))

245. Functions def printMax (x, y): '''Prints the maximum of two numbers. The two values must be integers.''' x = int(x) # convert to integers, if possible y = int(y) if x > y: r eturn x else : r eturn y printMax( 3 , 5 )

246. Last important thing about variable >>> a=[1,2,3]

247. >>> b=a

248. >>> a[0]=4

249. >>> b

250. [4, 2, 3]

251. >>> a

252. [4, 2, 3]

253. If you want to have copy of a list use slice or import copy(use dir and find out)

254. File Handling Wap to read input from user and write back to file . =>fav_movie.py Wap to read set of numbers and write to file and read the file and add all the nos.=>pickling.py Swap 3 nos

255. Practice problem Get a particular line from a file = >get_particular_line.py

256. Get a list of zip file content and its size =>zip_length.py

257. Get current system name and ip=>details.py

258. Generate a random password using python

259. Modules Any python file is considered a module

260. Modules can be imported or run by themselves if __name__ == '__main__' : print ( 'This program is being run by itself' ) else : print ( 'I am being imported from another module' )

261. Recursion >>> def mysum(L):

262. ... if not L:

263. ... return 0

264. ... else:

265. # Call myself

266. ... return L[0] + mysum(L[1:])

267. >>> mysum([1, 2, 3, 4, 5])

268. 15

269. OOPs Python OOP is easy and simple

270. Class classname: Def name(): Objects instance=classname()

271. Note no new keyword

272. first_class.py

273. Isinstance()

274. issubclass()

275. Inbuilt functions hasattr(obj,attr)

276. getattr(obj,attr)=>retrieves attr value

277. setattr(obj,attr,val)=>set attr value

278. delattr(obj,attr)

279. first_class.py

280. add_book.py

281. More Resources http://wiki.python.org/moin/BeginnersGuide

282. http://www.python.org/doc/faq/

283. Learn Python in 10 minutes: http://www.poromenos.org/tutorials/python

284. Byte of Python: http://www.swaroopch.com/notes/Python

285. Dive Into Python: http://diveintopython.org/

286. Google

287. Any Questions ???

288. Thank You

Learn python

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