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# The purpose of this example is to demonstrate what is a dictionary in Python.
# This will also cover:
# functions,
# switch, and
# writing to text files.
# This function adds a birthday to the list of birthdays.
# Simple, isn't it?
# There's one flaw, though: In case we've already stored the data for that
# person, it will overwrite that data.
def add_birthday(person, day, birthdays):
birthdays[person] = day
# This does the same as the previous function, but checks if we already have
# the birthday of that person remembered and warns us in that case.
# Practice: This function is not used in this example, only defined.
# Could you change the code so that it is used instead of
# the default "add_birthday" function?
def add_birthday_safer(person, day, birthdays):
if birthdays.has_key(person):
print "You've already entered " + person + "'s birthday as:",
print birthdays[person]
print "Would you like to overwrite that with " + day + " (y/n)?"
response = raw_input("Response: ")
# Practice: Add some more possible answers (like with capital letters)
if response == "n" or response == "no":
# "return" marks the end of the function
return
else:
birthdays[person] = day
# To change an existing record: just overwrite whatever was there before!
# It will simply add a new record if there wasn't a person with the given name,
# and that is fine. Because of that, we don't have to check if the record exists.
def change_birthday(person, day, birthdays):
birthdays[person] = day
# This function deletes a birthday.
def forget_birthday(person, birthdays):
if birthdays.has_key(person):
del birthdays[person]
else:
print "No such person."
# This function check if it's anyone's birthday today.
def check_birthdays(birthdays):
# this will get us the today's date in the form ddmm, the same
# as we enter it. We don't need the year, most people have birthdays
# each year. :)
# Practice: Who doesn't?
today = time.strftime("%d%m")
none_today = True
for person in birthdays:
bday = birthdays[person]
# How do we know which birthday is it?
# Easy: current year - birth year.
# time.strftime("%Y") gets us the current year, and the birth year
# is written in "bday" variable, from 4th index to the last.
# Since both are written as strings, we have to turn them to numbers
# before we can subtract them, and we do that by passing them to the int()
# function. When they are subtracted, turn the result back into a string,
# by passing it to the str() function.
which = str( int(time.strftime("%Y")) - int(bday[4:]) )
if bday[0:4] == today:
print "It's " + person + "'s " + which + ". birthday, yay!"
none_today = False
if none_today:
print "No birthdays today."
# Practice: Could we make the output of this function nicer?
# For example, change it to the form of dd.mm.yyyy instead of ddmmyyy ?
def print_birthdays(birthdays):
for person, day in birthdays.items():
print person + " was born on " + day + "."
if len(birthdays.items()) == 0:
print "There are no birthdays memorised."
# This function takes a name and finds that person's birthday.
def find_birthday(name, birthdays):
if birthdays.has_key(name):
print name + "'s birthday is on: " + birthdays[name]
else:
print "You never entered " + name + "'s birthday!"
def save_to_file(filename, bdays):
# Warning: If there already exists a file with this name, opening it in "w"rite
# mode will delete the existing file and create a blank one!
# Opening in "a"ppend mode adds everything to the end of an existing file,
# but we won't use it here.
# Practice: Try writing a program which appends to text files to see how it works.
f = open(filename, "w")
# Practice: What does str(bdays) give us? Try it on a dictionary variable!
text = str(bdays)
f.write(text)
f.close()
def load_from_file(filename):
my_file = open(filename, "r")
text_from_file = my_file.read()
# eval() takes text and then runs it as if it were Python code.
# For us, it will turn a textual representation of a dictionary to a functional
# Python dictionary.
bday_dictionary = eval(text_from_file)
# Return that to whoever called load_from_file() in the first place.
return bday_dictionary
# This function checks whether the string you entered is actually a date.
# What are the things we check for?
# What could also be checked? Is it possible to enter a future date now?
def validate_date(user_input):
if len(user_input) != 8:
return False
try:
int(user_input)
except:
return False
if int(user_input) < 0:
return False
if int(user_input[0:2]) > 31:
return False
if int(user_input[2:4]) > 12:
return False
if int(user_input[4:8]) > int(time.strftime("%Y")):
return False
return True
# This function displays the menu which you see when you run the program.
def menu():
# Here we will store all the birthday data. Notice the {} - that's how we
# define that a variable is a dictionary.
# This will get us an empty dictionary, and we'll see how to fill it
# with data in a moment.
birthdays = {}
# We'll display the menu in an infinite loop.
# The condition in while() will always be true, since it's, well.. True.
# The entire function, though, will end when the user enters "7".
while (True):
# Print thirty # and move to a new line.
print "#" * 60 + "\n"
print "Please choose from the following: "
print "\t1. Print all birthdays we have remembered."
print "\t2. Check if someone's birthday is today."
print "\t3. Find someone's birthday."
print "\t4. Add a new birthday."
print "\t5. Change the data for an existing birthday."
print "\t6. Delete an existing birthday."
print "\t7. Write all birthdays to a file."
print "\t8. Load birthdays from a file."
print "\t9. Exit."
choice = raw_input("Your choice: ")
if choice == "1":
print_birthdays(birthdays)
elif choice == "2":
check_birthdays(birthdays)
elif choice == "3":
print "Enter your friend's name: "
name = raw_input()
find_birthday(name, birthdays)
elif choice == "4":
print "Enter your friend's name: "
name = raw_input()
print "Enter " + name + "'s birthday (ddmmyyyy): "
birthday = raw_input()
if validate_date(birthday):
add_birthday(name, birthday, birthdays)
else:
print "That is not a valid birthday."
elif choice == "5":
print "Enter your friend's name: "
name = raw_input()
print "Enter " + name + "'s birthday (ddmmyyyy): "
birthday = raw_input()
if validate_date(birthday):
change_birthday(name, birthday, birthdays)
else:
print "That is not a valid birthday."
elif choice == "6":
print "Enter your friend's name: "
name = raw_input()
forget_birthday(name, birthdays)
elif choice == "7":
print "Enter the name of the file in which to store: "
filename = raw_input()
print "Location of that file (can be blank): "
filename = raw_input() + filename
save_to_file(filename, birthdays)
elif choice == "8":
print "Name of the file with stored birthdays: "
filename = raw_input()
print "Location of that file (can be blank): "
filename = raw_input() + filename
# Warning! Doing this will overwrite anything we're put in our dictionary
# so far with that is saved in that file.
birthdays = load_from_file(filename)
# Practice: Currently, there's no way for a user to load data from two
# different files at once. It would be possible to ask for two filenames
# a write a function which would take those two filenames, read from both
# files and combine their content into one dictionary.
# A hint: dictionaries have a method called "update",
# look it up to see what it does!
elif choice == "9":
return
else:
print "That is not a valid option!"
raw_input("Press enter to continue...")
# This is where our program starts executing. It enters the menu() function and
# runs it until you choose to leave.
print "Welcome to the birthday reminder."
import time
menu()
print "Exiting the birthday reminder... Bye!"
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