1. file_handle.py
2. yearborn.py
3. years_dictionary2.py
4. years_dictionary.py

# Demonstrate file handling exception
# Sara Sprenkle

import sys

def main():
    infileName = input("What file do you want to read? ")
    
    try:
        inFile = open(infileName, "r")
        # normally, would be doing some sort of processing of the file here.
        inFile.close()
    except IOError as 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 = input("What file do you want to write? ")
   
    try:
        outFile = open(outfileName, "w")
        # normally, would be doing some sort of processing of the file here.
        outFile.close()
    except IOError as exc:
        print("Error writing \"" + outfileName + "\".")
        print(exc)
    
main()

# Demonstrate validating user input
# Modified from a student's code from lab assignment

import sys

def main():
    #Program mission statement
    print("This program determines your birth year")
    print("given your age and the current year \n")

    try:
        age = int(input("Enter your age: "))
        # note difference if use eval instead of int in above 
        currentyear = int(input("Enter the current year: "))
    except:
        print("ERROR: Your input was not in the correct form.")
        print("Enter integers for your age and the current year")
        sys.exit()
    
    if age < 0 or age > 115:
        print("Come on: you have to be a reasonable age.")
    elif currentyear < 0:
        print("You need to have a positive year.")
    else:
        #Subtract age from current year
        birthyear=currentyear - age
        #Display output to the user
        print("You were either born in", birthyear, "or", birthyear-1)


main()

# Given a file of the form <lastname> <year>
# creates a mapping between the years and the number of students.
# by CSCI 111

FILENAME="data/years.dat"

# open the file for reading
yearsFile = open(FILENAME, "r")

yearsToNumStudents = {}

for line in yearsFile:
    # split the line into its components
    # we can ignore the trailing \n because split handles that for us
    data = line.split()
    lastname = data[0] # we're not using the lastname 
    year = data[-1] # we know the last thing is the year
    
    # if the class year is not in the dictionary,
    # create a new mapping
    if year not in yearsToNumStudents:
        yearsToNumStudents[year] = 1
    # otherwise, update the mapping
    else:
        yearsToNumStudents[year] += 1
    """
    if yearsToNumStudents.get(year) is None:
        yearsToNumStudents[year] = 1
    # otherwise
    else:
        yearsToNumStudents[year] += 1
        yearsToNumStudents[year] = yearsToNumStudents[year] + 1
        yearsToNumStudents[year] = yearsToNumStudents.get(year) + 1
    """
yearsFile.close()

print( yearsToNumStudents )

for classYear in sorted(yearsToNumStudents):
    print(classYear, yearsToNumStudents[classYear])

# Given a file of the form <lastname> <class>
# creates a mapping between the last names and class
# by CSCI 111

FILENAME="data/years.dat"

# open the file for reading
yearsFile = open(FILENAME, "r")

lastnameToYear = {}

for line in yearsFile:
    # split the line into its components
    # we can ignore the trailing \n because split handles that for us
    data = line.split()
    lastname = data[0:-1]
    year = data[-1]
    lastnameToYear[lastname] = year

yearsFile.close()

print( lastnameToYear )

for lastname in sorted(lastnameToYear):
    print(lastname, lastnameToYear[lastname])