Python: Need help making a simple program using arrays and loops

Baix · 08-01-2005, 02:36 PM

Hi all,
One of the first programs I like to try and make when first learning a programming language is a more advanced "hello world" type program. This is the basic flow of the program:

Code:

How many people are in the world? 3 
Person 1: Baix
Person 2: Bob 
Person 3: Tux 

Hello, Baix!
Hello, Bob!
Hello, Tux!

A loop would need to handle the imputing of the names (while i != total: ?) and the names would need to be put into an array to be printed using another loop to say hello to each name in the array.

I can't seem to figure out how to go about this in python. It seems to handle arrays (lists?) a bit differently than I've seen before. I'm sure once I see how this would be accomplished I would be able to figure out where I've been going wrong.

Thanks for any help!

shanenin · 08-01-2005, 03:36 PM

I am very new to programming, so I know just a little.

there are two common ways to store lists of data, the tuple, and the list
tuples are immutable, they can't be changed
lists are not immutable, they can be changed

you can set data to a tuple like this
array = (fist_element,second_element,third_element)

you can set data to a list like this
array = [fist_element,second_element,third_element]

the data in the list can be changed
array[1] = different_element

but with a tuple you ca't make any changes to the array, it is immutable.

Baix · 08-01-2005, 03:44 PM

I understand that part but having the user assign values to the array is whats confusing me. Thanks for the reply

shanenin · 08-01-2005, 03:46 PM

when you say user input, like using the read command with bash? Do you want the script to prompt you to enter input(names)?

Baix · 08-01-2005, 03:56 PM

I've gone back and italized what is inputed by the user. Basically it asks how many names it should ask for then asks for those names and stores them in an array. Then it spits the names back out saying "Hello, name"

Hope I'm making sense :-D.

shanenin · 08-01-2005, 03:56 PM

I think you are looking for the list method called append

Code:

>>> test_list =[]
>>> test_list.append('hh')
>>> print test_list
['hh']

edit//

this was added before reading your last post

shanenin · 08-01-2005, 04:09 PM

here is how I would do it

Code:

amount = int(raw_input('enter how many names you want to add to the list'))

name_list=[]  # this is needed to initialaize the list, so it can be appended to
for i in range(amount): # this will cause the loop to go three times
    name = raw_input('enter a name')
    name_list.append(name)

# this next loop loops thru it
for i in name_list:
    print "hello,",  i

Baix · 08-01-2005, 04:26 PM

Thanks a lot! Just had to clean it up a bit, that works just fine. I didn't know about the append nor how to initilize it.

Once again, thanks! Looks like I've got a bit more reading ahead of me

shanenin · 08-01-2005, 04:28 PM

your welcome. I am just glad I have something to offer.

exvor · 08-01-2005, 05:40 PM

Hey im not trying to hijack the thread but im only familliar with C

in reading this it has made me wonder about arrays

in this language can you specify and array without a size like a varible array for the program ?

shanenin · 08-01-2005, 09:15 PM

not quite sure what you are saying.

lmmier00 · 08-13-2005, 11:26 PM

For the "hello world" problem to be coded in python a for loop would be used. Code could be something like what follows:

population_number = input("How many people in the world? ")
person_list = []
for item in range(1, population_number + 1):
person = raw_input("Person " + str(item) + ": ")
person_list.append(person)
for x in person_list:
print "Hello " + x

Hope this helps.