1. ascii_dictionary.py
2. reportAvgData.py
3. using_dictionary.py
4. years_dictionary.py

# Demonstrate use of dictionary, using ASCII values
# By Sara Sprenkle

# create an empty dictionary
charToAscii = {}

ordValue = ord('a')

while ordValue <= ord('z'):
    # add mapping to dictionary of chr(ordValue) --> ordValue (ordinal value)
    char = chr(ordValue)
    charToAscii[char] = ordValue
    ordValue += 1

print(charToAscii)
print(sorted(charToAscii))

# demonstrate what happens if you try to look up a value that doesn't exist
print( charToAscii.get('!') )

print( charToAscii['!'] )

# Computes the average high temperature from multiple locations.
# Each location has an associated file that contains the daily
# high temperatures for last year at one location.
# Writes a report about the data in the form:
# <locationname> <avgtemp>
# <locationname> <avgtemp>
# ...
#
# Average temperature should be displayed to two decimal places
# Not covered in class
# By CSCI111

DATA_DIR = "data/"
LOCATIONS = ["alaska", "florida", "virginia"]
DATA_EXT = ".dat"
SUMMARY_FILE_NAME = "all_locations.dat"

def main():

    outFile = open("data/report.dat", "w")
    
    for location in LOCATIONS:
        dataFileName = DATA_DIR + location + DATA_EXT
        avgTemp = calculateAvgTemp(dataFileName)
        print("The average temperature in {:s} is {:.2f}".format(location, avgTemp))
        outFile.write( "{:s} {:.2f}\n".format(location, avgTemp))
        
    outFile.close()


def calculateAvgTemp( datafileName ):
    """
    Given the name of the data file formatted such that there is a 
    temperature on each line of the file, calculates and returns 
    the average of all the temperatures in the file as a float
    """

    # open the file
    dataFile = open( datafileName, "r")
    
    tempSum = 0
    numTemps = 0
    
    # read the file, line by line
    for line in dataFile:
        # convert the line to a float --> temperature
        temperature = float(line)
    
        # accumulate the temperatures
        tempSum = tempSum + temperature
    
        # accumulate the number of lines in the file
        numTemps += 1
    
    # close the file
    dataFile.close()
    
    # calculate the average
    average = tempSum/numTemps
   
    # return the average
    return average




main()

# Demonstrate use of dictionary using book index
# by Sara Sprenkle

# create an empty dictionary
topicToPageNumber = {}

# add entries to the dictionary
topicToPageNumber["integer"] = 20
topicToPageNumber["list"] = 60
topicToPageNumber["string"] = 45
topicToPageNumber["dictionary"] = 58
topicToPageNumber["float"] = 25


print("~~~~ topicToPageNumber dictionary: ~~~~~~")
# iterates through the keys in the dictionary
for topic in topicToPageNumber:
    # print the key and its associated value
    print(topic, topicToPageNumber[topic])

print()
# display the type that is returned by dictionary methods
print("type of dictionary.keys():", type(topicToPageNumber.keys()))
print("type of dictionary.values():", type(topicToPageNumber.values()))
print("The number of keys is", len(topicToPageNumber.keys()))

# iterate through the values
print("\nIterate through the values:")
for val in topicToPageNumber.values():
    print(val)
    
print("\nLook at the keys:")
keyList = list(topicToPageNumber.keys())
print("as <dict_keys>:\n", topicToPageNumber.keys())
print("as a list:\n", keyList)

print("\nPrint dictionary alphabetically by keys:")
# printing in order by key
keysSorted = list(topicToPageNumber.keys())
keysSorted.sort()

for topic in keysSorted:  # alternative: sorted(keysSorted)
    # print the key and its associated value
    print(topic, topicToPageNumber[topic])

print("\nPrint dictionary alphabetically by keys, again, in a different way:")

for topic in sorted(topicToPageNumber):
    print(topic, topicToPageNumber[topic])

print("\nWhat happens if you try to access a key that doesn't exist?")
# demonstrate what happens if you try to look up a value that doesn't exist
print( "Using get:", topicToPageNumber.get('anothertopic') )

print( "Using indexing:",  topicToPageNumber['anothertopic'] )

# Given a file of the form <firstname> <class>
# creates a mapping between the first names and class
# (In progress...)
# by CSCI 111

FILENAME="data/roster.dat"

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

# create our accumulator dictionary
nameToYear = {}

# go through each line
for line in yearsFile:
    # split at the space into the name and the year
    rosterList = line.split()
    
    # key is the name, value is the year
    name = rosterList[0]
    year = rosterList[1]
    
    # add mapping into the dictionary
    nameToYear[name] = year
    
    # Alternatively but not as readable: nameToYear[ rosterList[0] ] = rosterList[1]

yearsFile.close()

print(nameToYear)

#repeatedly (until the user enters nothing)
while True:
    # prompt for the student name and display their class year
    studentName = input("What is the student's name? ")
    
    if studentName == "":
        break
    
    if studentName in nameToYear:
        year = nameToYear[studentName]
        print(studentName, "is expected to graduate in", year)
    else:
        print(studentName, "is not on the roster")