PYTHON BASICS

 Dealing with Python basics







""" 

    This page covers max all the topics 

    conditional , loops , format string , string functions , lists

    Dictionaries , files , directory , functions , definitions , 

    modules , Exception handling

                                    

    Remaining parts is covered in next post

                                         """



for y in xrange(1,10):

print y



print [1,2,3] * 3

a,b,c = 3,5,6

print a,b,c

odd = [1,3,5,7,9]

even = [2,4,6,8,10]

print odd+even



# string formatting



form = ("john","jell",3.14)

fs = "hello"



print "%s hai %s king %d" % (fs,form[1],form[2])



# String formatting with list



mylis = [1,2,3]



print "This is my list %s" % (mylis)    



# Now we will go for basic string operations



one = "kri.sh.cdb.ry"



print "The length of the string  %s" %(len(one))

print "The index of h %s" %(one.index("h"))

print "The count of letter r %s" %(one.count("r"))

print "In capslock %s and the Lowerlock %s" %(one.upper(),one.lower())

print "The sub string %s" %(one[0:5])

print "They start with = %s and ends with = %s" %(one.startswith("kris"),one.endswith("ry"))

print "The splitting %s" %(one.split("."))



# Now goes with operations like boolesn comparison etc..



name = "John"

age = 23

if age == 2 and name == "John":

   print "ok"

else:

   print "no ok"



i = 1

while (i<10): 

print i 

i=i+1

name,king = "krishcdbry","krishcdbry"



if name in[king]:

  print "yess"





if name is king:

   print "hey"  



count = 1

while True:

print count 

count += 1

if count > 5:

break

c=0

while True: 

c += 1

if c%2==0:

continue

if c>5:

break  



print c 



# Function 



def my_krish(n): 

print "hello krish the number is %s" %(n)





def one_add(a,b):

    my_krish(a+b)



def one_main(name1,name2):

print "Hello dudes %s and %s" %(name1,name2)







one_main("krishcdbry","kingcdbry")

one_add(5,3)





# Going to objects and classes



class Krish:

car_name,car_cost,color = "Ferrari",7000000,"blue" 





car_one  = Krish()

car_one.car_name , car_one.car_cost,car_one.color = "Buggati",10000000,"Merun"



print Krish().color

print car_one.color









# Dictionaries 





krishbook = {

     "krish":909090909,

   "Mohan": 964298874

}



# OR 



krishbooks = {}

krishbooks["name"] = 9099900

krishbooks["one"] = 00123213123



for name, number in krishbooks.iteritems():

    print "Phone number of %s is %d" % (name, number)



del krishbook["krish"]



print krishbook



krishbooks.pop("one")



print krishbooks



# Dealing with files



"""  Creating the file not exists  """



fi = open("new.txt","wb")

fi.write("Hello this is krishcdbry's file buddy \n \n \n and This is just a cool python script");

fi.close()



""" Reading the file """



fi = open("new.txt","r+")

str = fi.read()

print " Reading the file =  %s "%(str)

fi.tell()   # Tells the position of the cursor 

fi.seek(0,10)   # Repositioning the cursor

fi.close()   # closes the file 





# Renaming the file name



# importing the OS module will helps to rename the files



import os      # this imports the os module....!



os.rename("old_file_name.txt","new_name.txt")



# We can remove the file .. simply delete 



os.remove("file_name") 



# mkdir - for making new directory.....! 



os.mkdir("new_dir")



# chdir  - change the dir......!



os.chdir("dir_name")



# pwd current working directory...!



os.getcwd()



# rmdir - remove the directory



os.rmdir("dir_name")  



# Exception handling





try:

   fh = open("jahe.txt","r+")

   fh.write("Hai this is another file....!")

except IOError:

  print "Their is no file found with name jahe.txt check it once buddy"   

else:

  print "File found dude"  





  # raise -  we can raise Exception



  def function_name(level):

      if level<1:

         raise "Their is an error in this level"

         # the code below would not be executre if we raise this exception

read more...