This example works as a birthday reminder. It demonstrates the use of dictionaries and several other things (like functions) already covered in the existing examples, but now put in a larger program. PS. I now notice I've pushed this code with "switch" in comments instead of "if-else", I'll change that. Dinko Galetic diff --git a/data/GSOC examples/birthday reminder b/data/GSOC examples/birthday new file mode 100644 index 0000000..eca9458 --- /dev/null +++ b/data/GSOC examples/birthday reminder @@ -0,0 +1,201 @@ +# 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 exist +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 in + # function. When they are subtracted, turn the result back into a strin + # 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" + # 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 + 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 functi + # 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 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() + add_birthday(name, birthday, birthdays) + + elif choice == "5": + print "Enter your friend's name: " + name = raw_input() + print "Enter " + name + "'s birthday (ddmmyyyy): " + birthday = raw_input() + change_birthday(name, birthday, birthdays) + + 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 dict + # 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 filename + # a write a function which would take those two filenames, read from bo + # 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 + +# 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!"