1.1) Create a list that contains the names of 5 students of this
class.  (Do not ask for input to do that, simply create the list.)
Print the list. Ask the user to input one more name and append it to
the list.  Print the list. Ask a user to input a number. Print the
name that has that number as index. Add "John Smith" and "Mary Miller"
to the beginning of the list (by using "+"). Print the list.

#!/usr/bin/env python

students = ["Paul Miller", "Kathy Jones", "Susan Smith", "John Doe",
"James Black"]

print "The following students are in the class:", students

new_student = raw_input("Type the name of another student: ")
students.append(new_student)
print "The following students are in the class:", students

number = input("Enter a number: ")
print "The student number", number + 1, "is", students[number]

students = ["John Smith", "Mary Miller"] + students
print "The following students are in the class:", students

----------------

2.1) Continue with the script from 1.1): Print the list. Remove the
last name from the list. Print the list. Ask a user to type a name. Check
whether that name is in the list: if it is then delete it from the
list. Otherwise add it at the end. Create a copy of the list in
reverse order. Print the original list and the reverse list.

#!/usr/bin/env python

students = ["Paul Miller", "Kathy Jones", "Susan Smith", "John Doe",
"James Black"]

print "The following students are in the class:", students

del students[-1]
print "The following students are in the class:", students

another_student = raw_input("Enter the name of a student to be added/deleted: ")
if another_student in students:
        students.remove(another_student)
else:
        students.append(another_student)

print "The following students are in the class:", students

more_students = students[:]

more_students.reverse()
print students
print more_students

----------------

3.1) Use the list of student names from exercise 2.1): Create a
for loop that prints for each student "hello student_name, how are
you?" where student_name is replaced by the name of the student.

#!/usr/bin/env python
#

students = ["Paul Miller", "Kathy Jones", "Susan Smith", "John Doe",
"James Black"]

for student in students:
    print "Hello", student + ", how are you?"

----------------

3.2) Optional: Use the list of student names from the previous
exercise. Create a for loop that asks the user for every name whether
they would like to keep the name or delete it. Delete the names which
the user no longer wants. Hint: you cannot go through a list using a
for loop and delete elements from the same list simulatenously because
in that way the for loop will not reach all elements. You can either
use a second copy of the list for the loop condition or you can use a
second empty list to which you append the elements that the user does
not want to delete.

#!/usr/bin/env python
#
# first version

students = ["Paul Miller", "Kathy Jones", "Susan Smith", "John Doe",
"James Black"]

new_students = students[:]

for student in new_students:
     print "Do you want to keep student", student, "?"
     answer = raw_input ("yes/no ")
     if answer != "yes":
         students.remove(student)
print students

----------------

#!/usr/bin/env python
#
# second version

students = ["Paul Miller", "Kathy Jones", "Susan Smith", "John Doe",
"James Black"]

new_students = []

for student in students:
     print "Do you want to keep student", student, "?"
     answer = raw_input ("yes/no ")
     if answer == "yes":
         new_students.append(student)

students = new_students
print students

---------------
4.1) Modify the program so that the lines are printed in reverse
order.

#!/usr/bin/env python
#
# Program to read and print a file 
#
file = open("alice.txt","r")
text = file.readlines()
file.close()

text.reverse()

for line in text:
    print line,
print 


---------------
4.2) Output to another file instead of the screen. First, let your
script overwrite the output file, then change the script so that it
appends the output to an existing file.

file = open("alice.txt","r")
text = file.readlines()
file.close()

file2 = open ("output.txt", "w")
file2.writelines(text)
file2.close

file2 = open ("append.txt", "a")
file2.writelines(text)
file2.close

---------------
4.3) Modify the program so that each line is printed with a line
number at the beginning.

#!/usr/bin/env python
#
# Program to read and print a file 
#
file = open("alice.txt","r")
text = file.readlines()
file.close()

counter = 1
for line in text:
    print counter, line,
    counter = counter +1
print 




---------------
6.1) Create a second dictionary (such as "age") and print its values
as well.

#!/usr/bin/env python
#
# a dictionary

relatives ={"Lisa" : "daughter", "Bart" : "son", "Marge" : "mother",
"Homer" : "father", "Santa" : "dog"}

age ={"Lisa" : 8, "Bart" : 10, "Marge" : 35,
"Homer" : 40, "Santa" : 2}

for member in relatives.keys():
    print member, "is a", relatives[member], "and is", age[member], \
    "years old"