Contents
- ascii_dictionary.py
- using_dictionary.py
- years_dictionary.py
ascii_dictionary.py 1/3
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# Demonstrate use of dictionary, using ASCII values
# Sara Sprenkle
# create an empty dictionary
ascii= {}
ordValue = ord('a')
while ordValue <= ord('z'):
# add mapping to dictionary of chr(ordValue) --> ordValue (ordinal value)
char = chr(ordValue)
ascii[char] = ordValue
ordValue += 1
print(ascii)
using_dictionary.py 2/3
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# Demonstrate use of dictionary, using ASCII values
#
# create an empty dictionary
ascii= {}
x = ord('a')
while x <= ord('z'):
# add mapping to dictionary of chr(x) --> x (ordinal value)
char = chr(x)
ascii[char] = x
x+=1
# iterates through the keys in the dictionary
for letter in ascii:
# print the key and its associated value
print(letter, ascii[letter])
# display the type that is returned by dictionary methods
print(type(ascii.keys()))
print(type(ascii.values()))
print("The number of keys is", len(ascii.keys()))
# iterate through the values
print("Iterate through the values:")
for val in ascii.values():
print(val)
keyList = list(ascii.keys())
print("as <dict_keys>:\n", ascii.keys())
print("as a list:\n", keyList)
# printing in order by key
keysSorted = list(ascii.keys())
keysSorted.sort()
for letter in keysSorted: # alternative: sorted(keysSorted)
# print the key and its associated value
print(letter, ascii[letter])
for letter in sorted(ascii):
print(letter, ascii[letter])
years_dictionary.py 3/3
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# 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")
# create an empty dictionary that maps the student's last name to the class year
lastnameToClassMap = {}
for line in yearsFile:
# form of the line is:
# lastname class
data = line.split()
lastname = data[0] # first element is the lastname
classname = data[1] # second element is the class
# add a mapping from the lastname to the classname
lastnameToClassMap[lastname] = classname
yearsFile.close()
# Show that reading in the file worked correctly:
#for lastname in sorted(lastnameToClassMap):
# print(lastname, "-->", lastnameToClassMap[lastname])
while True:
lastname = input("What student do you want to check on? ")
# Issue with this solution, alone:
# print(lastname, "is a", lastnameToClassMap[lastname])
# --> If user enters a lastname that doesn't exist as a key in the
# dictionary, program exits with a KeyError.
# Solution: first, check if that lastname is a valid key
if lastname in lastnameToClassMap:
print(lastname, "is a", lastnameToClassMap[lastname])
else:
print(lastname, "is not a valid key")
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