[Tutorial] Learning programming with Python, part 1

[Acid_Snake]

Advertising

I want to start this Topic to introduce people on the basics of Python programming.

Intro:
Python is a high-level object oriented interpreted programming language.

A simple app:
In every programming language is best to start creating a basic app, this app is usually a hello world and in python it can be as simple as:

Code: Select all

print "Hello World"

This will print the text Hello World and exit.

Strings and integers:
In python there are strings and there are integers, a string uses double quotes or single quote:

Code: Select all

print "Hello World"
print 'Hello World'

They both do the same.
Integers don't use any type of quotation:

Code: Select all

print 1

If an integer uses quotation it becomes a string, for example:

Code: Select all

print 1+1

will print out number 2, but this:

Code: Select all

print "1"+"1"

will print out 11 the same way this:

Code: Select all

print "hello"+"world"

will print out helloworld
It is important to know that you can't add (+) a string and an integer:

Code: Select all

print 1 + "hello"

will produce this error:

Code: Select all

TypeError: unsupported operand type(s) for +: 'int' and 'str'

To do so, the integer has to be converted into a string:

Code: Select all

print str(1) + "hello"

Now you know the basics of strings and integers in python.
Next up: variables.
Stay tuned for more on this crazy sitcom.
Next: http://wololo.net/talk/viewtopic.php?f=37&t=11843

[qwikrazor87]

Advertising

Is that really the outcome in Python when adding two stringed numbers? "1"+"1" outcome 11?
I'm sorry, I'm not a Python programmer. I just tried that out in Lua and it converted the stringed numbers into integers and produced the result as if they were integers in the first place. In my case I tried:
"7" + "8" and the result was 15

[Acid_Snake]

Is that really the outcome in Python when adding two stringed numbers? "1"+"1" outcome 11?
I'm sorry, I'm not a Python programmer. I just tried that out in Lua and it converted the stringed numbers into integers and produced the result as if they were integers in the first place. In my case I tried:
"7" + "8" and the result was 15

In python if you use quotes then it becomes string, so "1"+"1" becomes "11"(a one next to a one) the same way "1"+"hello" becomes "1hello", in python integers dont use quotes, so you use 1+1 and it returns a 2.
I recommend you install and use the python interpreter instead of lua cause programming languages are different.

[Sparky]

Why are you using Python 2 and not 3 ?

[Wdingdong]

Is that really the outcome in Python when adding two stringed numbers? "1"+"1" outcome 11?
I'm sorry, I'm not a Python programmer. I just tried that out in Lua and it converted the stringed numbers into integers and produced the result as if they were integers in the first place. In my case I tried:
"7" + "8" and the result was 15

Here the '+' sign is not a arithimatic operator of addition of numbers, but it is a concatenation operator which joins two strings.

[Acid_Snake]

Why are you using Python 2 and not 3 ?

I prefer python 2.7, it has the new stuff from python 3 with the syntax intact. You can however make code compatible with both:

Code: Select all

print("Hello World")

this will work for both.

[m0skit0]

Nice, thanks for the tuto I suggest you linking to next lesson in your first post, because I'm thinking about sticking it

[Acid_Snake]

Nice, thanks for the tuto I suggest you linking to next lesson in your first post, because I'm thinking about sticking it

Done. thank you

[lacrimosaangel]

Ooooh thanks for this! Will be reading all of your little tutes
Someone did try explaining python to me before but they made it sound so confusing I'm used to programming with Java so plenty used to strings and integers etc..

Can I use Text pad for Python and then compile and run via cmd prompt or is it best to download a particular python-specific compiler?

[Acid_Snake]

python is an interpreted language, it doesn't need compiling (well, actually it does need compiling but that is done by the interpreter at run time so you don't have to worry about that)