1. String 

"hello"+"world"   hellowworld
"hellow"*3        "hellohellohello"

"hello"[-1]       "o" from end
"hello"[1:4]       ell"
len("hello")       5

2. List

a= [99, "Bottles of beers", ["on", "the", "wall"]]
same operator as strings

a[0]=98] 
a[1:2] = ["bottles","of","beer"]
-> [98, "bottles", "of", "beer", ["on", "the","wall"]]
del a[-1] -> [98, "bottles", "of", "beer"]

a=range[5]    [0,1,2,3,4]
a.apend(5)    [0,1,2,3,4,5]
a.pop()       [0,1,2,3,4]
a.reverse()   [4,3,2,1,0]
a.sort()      [0,1,2,3,4]

3 hash table

d= {"duck": "eend", "water": "water"}
d["duck"] ->"eend"
d["duck"]="duik" -> {"duck":"duik","back":"rug"
d.keys() ["duck", "back"]
d.values()
d.items() 
d.has_key("duck") ->1 

4. assignment

a=[1,2,3]; b=a
a.append(4) 
print b
[1,2,3,4]

5. control structure

if cond:
  statements
elif cond:
  statements 
else: 
  statements
 
while cond:
 statements

for var in sequence:
 statements

for i in rage 5
   print i

indentation

6. functions 

def gcd (a,b):
"greatest common divisor" 
while a!=0: 
  a, b=b%a, a
return b

if __name__=="__main__":

  print gcd(4,10)

7. input and exceptions


a=raw_input("how old are you?")

try:
   a=int(a)
   print "you are"+a 
except ValueError: 
   print "not a number"