Contents
- birthyear3.py
- file_handle.py
- mystery.py
- twod_exercises.py
birthyear3.py 1/4
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# Demonstrate validating user input
# Made from a student's code from Lab 1
def main():
#Program mission statement
print "This program determines your birth year"
print "given your age and the current year \n"
age = getPosIntegerInput("Enter your age: ")
currentyear = getPosIntegerInput("Enter the current year: ")
if age > 115:
print "That is not a reasonable age"
else:
birthyear=currentyear - age
#Display output to the user
print "You were either born in", birthyear, "or", birthyear-1
def getPosIntegerInput(prompt):
"""Repeatedly prompts the user for input until the user
enters a positive integer."""
while True:
try:
value=input(prompt)
if value > 0:
return value
else:
print "Number is out of range"
except:
print
print "ERROR: Your input was not in the correct format."
print "You must enter a positive integer value"
main()
file_handle.py 2/4
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# Demonstrate file handling exception
# Sara Sprenkle
import sys
def main():
infileName = raw_input("What file do you want to read? ")
try:
inFile = file(infileName, "r")
except IOError, exc: # exc is the name of the thrown exception
print "Error reading \"" + infileName + "\"."
# could be a variety of different problems, so print out
# the exception
print exc
sys.exit(1)
outfileName = raw_input("What file do you want to write? ")
try:
outFile = file(outfileName, "w")
except IOError, exc:
print "Error writing \"" + outfileName + "\"."
print exc
main()
mystery.py 3/4
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# Practice with 2D lists
# by Sara Sprenkle
def main():
matrix = createMatrix()
print "Before:"
print matrix
mystery(matrix)
print "After:"
print matrix
def mystery(a):
""" "run" this on A, at right """
for row in range( len(a) ):
for col in range( len(a[0]) ):
if row == col:
a[row][col] = 42
else:
a[row][col] += 1
def createMatrix():
a0 = range(1,5)
a1 = range(5,9)
a2 = range(9,13)
a = []
a.append(a0)
a.append(a1)
a.append(a2)
return a
main()
twod_exercises.py 4/4
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# Practice with 2D Lists
# Sara Sprenkle
def main():
rows = input("How many rows? ")
columns = input("How many columns? ")
print
print "Correct Matrix Creation:"
print '-'*30
matrix = create2DList(rows, columns)
print matrix
print "\nAssigning matrix[1][2]=3"
matrix[1][2] = 3
print "Result: "
print matrix
print
print "*"*50
print "Incorrect Matrix Creation:"
print '-'*30
matrix = noCreate2DList(rows, columns)
print matrix
print "\nAssigning matrix[1][2]=3"
print "Result: "
matrix[1][2] = 3
print matrix
def create2DList(rows, cols):
"""Returns a two-dimensional list filled with 0s that is 'rows' tall and
'cols' wide."""
twodlist = []
for row in xrange(rows):
row = []
for col in xrange(cols):
row.append(0)
twodlist.append(row)
return twodlist
def noCreate2DList(rows, cols):
"""Does not create a 2D list because each 'row' points to the same point in
memory."""
twodlist = []
onerow = []
for col in xrange(cols):
onerow.append(0)
for row in xrange(rows):
twodlist.append(onerow)
return twodlist
main()
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