lesson 1: quick introduction to the python language (www.python.org)


1) open up a terminal so you can type unix commands

2) type the command

	python

   you should see some text telling you what version it
   is, followed by the prompt ">>>" wehre you can type
   more (now python) commands:

	a=1
	b=2

	a+b

   and it will say:       3   (surprised?)
   or

	c=a+b

	print c

	print a,b,c


	print "Hello a=",a

	print "Hello a=%g b=%g c=%g"   %   (a,b,c)

	A=[1,2,3]
	B=[10,11,12]
	A+B

   Note that 'a' is different from 'A'

	for i in A<RETURN>
	   print i<RETURN>
        <RETURN>

   Note the peculiar indentation you need to use, and only
   after the 3rd RETURN will it execute this 'for' loop



3) Many functions in python come from "modules" that need to
   be loaded. 

	import math

   now you have some math 

	help(math)

	math.sqrt(4)
	math.pi



PTO:  don't forget items 4) and 5) on the other side of this page....



4) make a table with numbers in a file, with some editor
   like emacs, vi, 

   Look at the file

	more table1

   Count how many characters,lines and words

	wc table1

   
5) Now process the file in python

	file = open('table1','r')
	lines = file.readlines()
	file.close()

	lines				it is

	len(lines)			check if it's the same as "wc" gave
				


	sum = 0
	for l in lines:
	  sum = sum + float(l)
        print sum


   Type control-d to exit from python