1

Python strukturalno, objektno (sve je objekt!), funkcionalno

and del for is raise

assert elif from lambda return

break else global not try

class except import or while

continue exec if pass yield

def finally in print 29 riječi

2

# -*- coding: cp1250 -*-ime = raw_input ("Kako se zoveš? ")print imebroj=input('Tvoj najdraži broj? ')print broj, 'puta hura za:', broj*ime

Interpreter: Python Shell 2.5 – IDLE + batch; PythonWin, PyScripter,...

>>> Kako se zoveš? miki miki Tvoj najdraži broj? 33 puta hura za: miki miki miki >>>

3

Modules (+classes, functions, vars) import module

koristiti : module.name from module import name

koristiti : name

import mathx = 1.0while x < 10.0: print x, '\t', math.log(x) x = x + 1.0

1.0 0.02.0 0.693147180563.0 1.098612288674.0 1.386294361125.0 1.609437912436.0 1.791759469237.0 1.945910149068.0 2.079441541689.0 2.19722457734>>>

4

Numbers, sequences, dictionaries

integerlong integerfloat, doublecomplex

0101 84 -237 0x80

16384L -0x4E8L 017L -2147483648l

3.1416 4.2E-10 -90. 6.022e23 6.23+1.5j -1.23-875J -.0224+0j

stringlisttuple

aString = 'Hello World!'

aList = [123,'abc', 4.56,['inner','l'], 7-9j]

aTuple = (123,'abc',4.56,['inner', 't'],7-9j)

dictionary dict2 = {'name': 'earth', 'port': 80} print 'host %s is running on port %d' % \ …

(dict2['name'], dict2['port'])

5

Conditionals and loops

if if not warn and (system_load >= 10): print "WARNING: losing resources"

else

(elif)

if (balance > 0.00): if ((balance - amt) > min_bal) and (atm_cashout() == 1): print "here's your cash; please take all bills." ..else:

print "your balance is zero or negative"

for for eachLetter in 'Names':

print 'current letter:', eachLetter nameList=['Walter', "Nicole", 'Steven', 'Henry'] for eachName in nameList:

print eachName, "Lim"

... while, break, continue

6

Indexing, slicing, formating, ....insert, .new, .extend, .append., .index, .pop(), len(), ...

slicing

indexing

>>> li = ["a", "b", "mpilgrim", "z", "example"]>>> li['a', 'b', 'mpilgrim', 'z', 'example']>>> li[−3]'mpilgrim'>>> li[1:−1]['b', 'mpilgrim', 'z']>>> li.insert(2, "new")>>> li['a', 'b', 'new', 'mpilgrim', 'z', 'example']>>> li.pop()'example' >>> li = [1, 2] * 3>>> li[1, 2, 1, 2, 1, 2]>>> k = "uid">>> v = "sa">>> "%s=%s" % (k, v)'uid=sa'

>>> range(7)[0, 1, 2, 3, 4, 5, 6]>>> (MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY) = range(7)>>> MONDAY0>>> TUESDAY1

7

keys, values, items ; .join, .split, ...

>>> params = {"server":"mpilgrim", "database":"master", "uid":"sa", "pwd":"secret"}>>> params.keys()['server', 'uid', 'database', 'pwd']>>> params.values()['mpilgrim', 'sa', 'master', 'secret']>>> params.items()[('server', 'mpilgrim'), ('uid', 'sa'), ('database', 'master'), ('pwd', 'secret')]>>> [k for k, v in params.items()]['server', 'uid', 'database', 'pwd']>>> [v for k, v in params.items()]['mpilgrim', 'sa', 'master', 'secret']>>> ["%s=%s" % (k, v) for k, v in params.items()]['server=mpilgrim', 'uid=sa', 'database=master', 'pwd=secret']>>>s = ";".join(["%s=%s" % (k, v) for k, v in params.items()])s'server=mpilgrim;uid=sa;database=master;pwd=secret'>>> s.split(";")['server=mpilgrim', 'uid=sa', 'database=master', 'pwd=secret']

8

Functions

def foo(): print 'in foo()' bar() def bar(): print 'in bar()'

>>> foo() in foo() in bar()

def taxMe(cost, rate=0.0825): … return cost + (cost * rate)

>>> taxMe(100) 108.25

>>> taxMe(100, 0.05) 105.0

Nije važa

n redoslij

ed

definicija fu

nkcija

def tupleVarArgs(arg1, arg2='defaultB', *theRest): print 'formal arg 1:', arg1 print 'formal arg 2:', arg2 for eachXtrArg in theRest: print 'another arg:', eachXtrArg

(non-keyword)

9

Function arguments (keyworded)

def dictVarArgs(arg1, arg2='defaultB', **theRest):

'display 2 regular args and keyword variable args'

print 'formal arg1:', arg1

print 'formal arg2:', arg2

for eachXtrArg in theRest.keys():

print 'Xtra arg %s: %s' % \

(eachXtrArg, str(theRest[eachXtrArg]))

dictVarArgs(1220, 740.0, c='grail')

dictVarArgs('mystery', arg2='tales', c=123, d='poe')

dictVarArgs('one', d=10, e='zoo', men=('freud','gaudi'))

formal arg1: 1220formal arg2: 740.0Xtra arg c: grail----------formal arg1: mysteryformal arg2: talesXtra arg c: 123Xtra arg d: poe----------formal arg1: oneformal arg2: defaultBXtra arg men: ('freud', 'gaudi')Xtra arg e: zooXtra arg d: 10>>>

10

Classclass AddrBookEntry: 'address book entry class' def __init__(self, nm, ph): self.name = nm self.phone = ph print 'Created instance for:', self.name def updatePhone(self, newph): self.phone = newph print 'Updated phone# for:', self.name

>>> john = AddrBookEntry('John Doe', '408-555-1212') Created instance for: John Doe >>> jane = AddrBookEntry('Jane Doe', '650-555-1212') Created instance for: Jane Doe

>>> john <__main__.AddrBookEntry instance at 80ee610> >>> john.name 'John Doe' >>> jane.phone '650-555-1212'

>>> john.updatePhone('415-555-1212') Updated phone# for: John Doe >>> john.phone

'415-555-1212'

11

Subclassclass AddrBookEntryWithEmail(AddrBookEntry): 'update address book entry class' def __init__(self, nm, ph, em): AddrBookEntry.__init__(self, nm, ph) self.email = em def updateEmail(self, newem): self.email = newem print 'Updated e-mail address for:', self.name

>>> john = AddrBookEntryWithEmail('John Doe, '408-555- 1212', 'john@spam.doe') Created instance for: John Doe >>> john.name 'John Doe' >>> john.email 'john@spam.doe' >>> john.updatePhone('415-555-1212') Updated phone# for: John Doe

>>> john.phone '415-555-1212' >>> john.updateEmail('john@doe.spam') Updated e-mail address for: John Doe>>> john.email 'john@doe.spam'

12

Multiple inheritanceclass P1: # parent class 1 def foo(self): print 'called P1-foo()' class P2: # parent class 2 def foo(self): print 'called P2-foo()' def bar(self): print 'called P2-bar()' class C1(P1,P2): # child 1 der.from P1,P2 pass class C2(P1,P2): # child 2 der.from P1,P2 def foo(self): print 'called C2-foo()' def bar(self): print 'called C2-bar()‘class GC(C1,C2): # define grandchild class pass # derived from C1 and C2

>> gc = GC()

>> gc.foo() # GC ? C1 ? P1 called P1-foo()

>> gc.bar() # GC ? C1 ? P1 ? P2 called P2-bar()

>> C2.foo(gc) called C2-foo()

13

Functional Programming

def add(x, y): lambda x, y: x + y return x + y

>>> a = lambda x, y=2: x + y >> a(3) 5 >> a(3,5)8 >> a(0)2 >> a(0,9)9

Built-in Functions: apply(), filter(), map(), reduce()

>>> map((lambda x: x+2),[0, 1, 2, 3, 4, 5]) [2, 3, 4, 5, 6, 7] >>> map(lambda x: x**2, [0, 1, 2, 3, 4, 5]) [0, 1, 4, 9, 16, 25] >>> map((lambda x: x**2),range(6)) [0, 1, 4, 9, 16, 25] >>> map(lambda x, y: (x+y, x-y), [1,3,5], [2,4,6]) [(3, -1), (7, -1), (11, -1)]

>>> def sum(x,y): return x+y >>> allNums = range(5) >>> total = 0 >>> for eachNum in allNums: ... total = sum(total, eachNum)...>>> print 'the total is:' total the total is: 10

>>> print 'the total is:', reduce((lambda x,y: x+y), range(5)) the total is: 10

14

Exceptions (try – except, assert, raise)

>>> aDict = {'host': 'earth', 'port': 80} >>> print aDict['server'] Traceback (innermost last): File "<stdin>", line 1, in ? KeyError: server

>>> try: … f = open('blah') … except IOError: … print 'could not open file' … could not open file

def safe_float(object): try: retval = float(object) except ValueError: retval = 'could not convert non-number to float‘ return retval

OverflowError , ZeroDivisionError ,

ValueError, IndexError, EOFError, ...

>>> safe_float('12.34') >>> safe_float('bad input') 12.34 'could not convert non-number to float'

15

TCP Timestamp

from socket import * <$nopage>from time import time, ctime

HOST = ''PORT = 21567BUFSIZ = 1024ADDR = (HOST, PORT)

tcpSerSock = socket(AF_INET, SOCK_STREAM)tcpSerSock.bind(ADDR)tcpSerSock.listen(5)

while 1: print 'waiting for connection…' tcpClisock, addr = tcpSerSock.accept() print '…connected from:', addr

while 1: data = tcpCliSock.recv(BUFSIZ) if not data: break <$nopage> tcpCliSock.send('[%s] %s' % \ ctime(time()), data)

tcpCliSock.close()tcpSerSock.close()

from socket import * <$nopage>

HOST = 'localhost'PORT = 21567BUFSIZ = 1024ADDR = (HOST, PORT)

tcpCliSock = socket(AF_INET, SOCK_STREAM)tcpCliSock.connect(ADDR)

while 1: data = raw_input('> ') if not data: break <$nopage> tcpCliSock.send(data) data = tcpCliSock.recv(1024) if not data: break <$nopage> print data

tcpCliSock.close()

Server

Client

16

Threadingfrom time import sleep, time, ctimedef loop0(): print 'start loop 0 at:', ctime(time()) sleep(4) print 'loop 0 done at:', ctime(time())def loop1(): print 'start loop 1 at:', ctime(time()) sleep(2) print 'loop 1 done at:', ctime(time())def main(): print 'starting…' loop0() loop1() print 'all DONE at:', ctime(time())if __name__ == '__main__': main()

>>> starting…start loop 0 at: Thu Apr 27 13:29:57 2006loop 0 done at: Thu Apr 27 13:30:01 2006start loop 1 at: Thu Apr 27 13:30:01 2006loop 1 done at: Thu Apr 27 13:30:03 2006all DONE at: Thu Apr 27 13:30:03 2006>>>

17

Executing Non-Python Programs

import os f = os.popen('uname -a')

data = f.readline() f.close()print data

Linux solo 2.2.13 #1 Mon Nov 8 15:08:22 CET 1999 i586 unknown

import os result = os.system('cat /etc/motd') Have a lot of fun… result 0

result = os.system('uname -a')

ret = os.fork() # spawn 2 processes, both return if ret == 0: # child returns with PID of 0 child_suite # child code else: # parent returns with child's PID parent_suite # parent code

os.fork(), os.exec*(), os.wait*()

18

Strings (NLTK), sys, os, web,...import sys # load the system libraryfor line in sys.stdin.readlines(): # for each line of input for word in line.split(): # for each word in the line if word.endswith('ing'): # does the word end in 'ing'? print word # if so, print the word

fruit = "banana"count = 0for char in fruit: if char == 'a': count = count + 1print count

import stringfruit = "banana"index = string.find(fruit, "a")print indexprint string.find("banana", "na", 3)print string.find("bob", "b", 1, 2)

def isLower(ch): return string.find(string.lowercase, ch) != -1def isLower(ch): return ch in string.lowercasedef isLower(ch): return 'a' <= ch <= 'z'

urllib, re, cgi, subprocess, HTMLParser, BeautifulSoup,...