python beginner talk slide

“Quotes”

 Perl is worse than Python because people wanted it worse
- Larry Wall, Creator of Perl
 Python fits your brain
- Bruce Eckel, Author: Thinking in Java
 Python is an excellent language & makes sensible
compromises.
- Peter Norvig. AI

Life is better without brackets

About Python
 very clear, readable syntax
 portable
 intuitive object orientation
 natural expression of procedural code
 full modularity, supporting hierarchical packages
 very high level dynamic data types
 extensive standard libraries and third party modules for
virtually every task
 extensions and modules easily written in C, C++ (or Java for
Jython, or .NET languages for IronPython)

Hello World
print “Hello World”
Hello World
a=6
print a;

6

a=‘Hello’
a=a+ 6

Errors a=a + str(6)

Strings
a=‘Hello’
a=“Hello”
a=“I Can’t do this”
a=“I ”Love” Python”
a=‘I “Love” Python’
Hello
Hello
I Can’t do this
I “Love” Python
I “Love” Python

a=“Hello”
print a[0]
print len(a)
print a[0:2]
print a[2:]

H
5
He
llo

a=“Hello”

print a[-1]
print a[-2:]

o
lo

More About str Class
print dir(str)
['__add__', '__class__', '__contains__', '__delattr__', '__doc__', '__eq__', '__ge__',
'__getattribute__', '__getitem__', '__getnewargs__', '__getslice__', '__gt__',
'__hash__', '__init__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__',
'__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__',
'__setattr__', '__str__', 'capitalize', 'center', 'count', 'decode', 'encode', 'endswith',
'expandtabs', 'find', 'index', 'isalnum', 'isalpha', 'isdigit', 'islower', 'isspace', 'istitle',
'isupper', 'join', 'ljust', 'lower', 'lstrip', 'partition', 'replace', 'rfind', 'rindex', 'rjust',
'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title',
'translate', 'upper', 'zfill']

Help Class
print help(str.find)
find(...)
S.find(sub [,start [,end]]) -> int

Return the lowest index in S where substring sub is found,
such that sub is contained within s[start,end]. Optional
arguments start and end are interpreted as in slice notation.

Return -1 on failure.

Some Basic Syntax(1)

n Odd
n is Odd and greater than 5
n divided by 2 or 5

Some Basic Syntax(1)
//Array Declaration
a=[]

2
1
5
Using Range:
2
1
5
True

List(1)
a=[3,1,5]
b=[4,2]
c=a+b
print c
del c[2]
print c
print len(c)
[3,1,5,4,2]
[3,1,4,2]
4

List(2)
(a,b)=([3,1,5],[4,2])
c=a+b
c= sorted(c)
print sorted(c)
print a==b
print sorted(c,reverse=True)
print c
print help(sorted)
[1,2,3,4,5]
False
[5,4,3,2,1]
[3, 1, 5, 4, 2]
Help on built-in function sorted in module __builtin__:
sorted(...)
sorted(iterable, cmp=None, key=None, reverse=False) --> new sorted list

List and Sort
a=['ax','aae','aac']
return 1,”Hello World”

def mFun(s):
a,b=mFun(“Hi”)
return s[-1]

print sorted(a,key=mFun)
print sorted(a,key=mFun,reverse=True)
print sorted(a,key=len)
['aac', 'aae', 'ax']
['ax', 'aae', 'aac']
['ax', 'aae', 'aac']

Tuples
a=(1,2,1)
print a[0]
print len(a)
b=[(1,2,3),(1,2,1),(1,4,1)]
print a in b

1
3
True

Tuples and sort
a=[(1,"b"),(2,"a"),(1,"e")]
print a
print sorted(a)
def myTSort(d):
return d[0]
print sorted(a,key=myTSort)
k=(1,”e”)
print k in a

[(1, 'b'), (2, 'a'), (1, 'e')]
[(1, 'b'), (1, 'e'), (2, 'a')]
[(2, 'a'), (1, 'b'), (1, 'e')]
True

Dictionary

d={}

d[‘a’]=‘alpha’
d[‘o’]=‘omega’
d[‘g’]=‘gamma’

print d[‘a’]
alpha

Dictionary
d={}
(d['a'],d['o'],d['g'])=("alpha","omega","gamma")
print d
print len(d)
{'a': 'alpha', 'g': 'gamma', 'o': 'omega'}
3

Check a value is in dictionary ???

‘a’ in d

Dictionary
d={}
print d[‘a’]
print d[‘x’] //???
print d.get(‘x’) // return None
print d.get(‘a’)

if(d.get(‘a’)){
print ‘Yes’
}

Dictionary
d={}
print d.keys()
print d.values()
print d.items()
['a', 'g', 'o']
['alpha', 'gamma', 'omega']
[('a', 'alpha'), ('g', 'gamma'), ('o', 'omega')]
What needs for sorted dictionary data(key order) ???
All data returns random order

for k in sorted( d.keys() ):
print d[k]

print sorted(d.keys())

Dictionary
print dir(dict)
['__class__', '__cmp__', '__contains__', '__delattr__', '__delitem__',
'__doc__', '__eq__', '__ge__', '__getattribute__', '__getitem__', '__gt__',
'__hash__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__ne__',
'__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__',
'__setitem__', '__str__', 'clear', 'copy', 'fromkeys', 'get', 'has_key', 'items',
'iteritems', 'iterkeys', 'itervalues', 'keys', 'pop', 'popitem', 'setdefault', 'update',
'values']

print help(dict)

print help(dict.items)

File
def readFile(fileName): // File write
f=open(fileName,'r') f=open(fileName,‘w')
f.write(data)
for line in f:
f.close()
print line,
f.close()

def readFile(fileName):
f=open(fileName,'r')
text=f.read()
print text
f.close()

f.seek(5)

Regular expression
import re

match=re.search('od',"God oder")
print match.group()
match=re.search(r'od',"God oder")
print match.group()

od
od

Regular expression
import re

print re.findall(r'ar+','a ar arr')
print re.findall(r'ar*','a ar arr')

['ar', 'arr']
['a', 'ar', 'arr']

+ for 1 or more
* for 0 or more

print dir(re)

Utility: OS
import os
print dir(os)
['F_OK', 'O_APPEND', 'O_BINARY', 'O_CREAT', 'O_EXCL',
'O_NOINHERIT', 'O_RANDOM', 'O_RDONLY', 'O_RDWR',
'O_SEQUENTIAL', 'UserDict', 'W_OK', 'X_OK', '_Environ', '__all__',
'__builtins__', '__doc__', '__file__', '__name__', '_copy_reg',
'_pickle_statvfs_result', 'abort', 'access', 'altsep', 'chdir', 'chmod', 'close',
'curdir', 'defpath', 'isatty', 'linesep', 'listdir', 'lseek', 'lstat', 'makedirs', 'mkdir',
'name', 'open', 'pardir', 'path', 'pathsep', 'pipe', 'popen', 'popen2', 'popen3',
'popen4', 'putenv', 'read', 'remove', 'removedirs', 'rename', 'renames', 'rmdir',
'sep', 'spawnl', 'spawnle', 'spawnv', 'spawnve', 'startfile', 'stat',
'stat_float_times', 'stat_result', 'statvfs_result', 'strerror', 'sys', 'system',
'tempnam', 'times', 'tmpfile', 'tmpnam', 'umask', 'unlink', 'unsetenv',
'urandom', 'utime', 'waitpid', 'walk', 'write']

Utility: OS
import os
print help(os.unlink)
unlink(...)
unlink(path)
Remove a file (same as remove(path)).

print help(os.rmdir)

rmdir(...)
rmdir(path)
Remove a directory.

Utility: HTTP request, URL

try:
pass
except:
pass
finally:
print “ok”

Some OOP

class MyClass(AnotherClass):
import myClass.py

Reserved Word
 and  finally  pass
 assert  for  print
 break  from  raise
 class  global  return
 continue  if  try
 def  import  while
 del  in
 elif  is
 else  lambda
 except  not
 exec  or

Code Source

http://jpython.blogspot.com/

Resource

 http://www.learnpython.org/
 http://learnpythonthehardway.org/book/
 http://code.google.com/edu/languages/google-
python-class/

 http://love-python.blogspot.com
 http://jpython.blogspot.com

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