Introduction to the Environment¶
There are three basic elements to your environment when working with Python:
- The Command Line
- The Interpreter
- The Editor
The Command Line (cli)¶
Having some facility on the command line is important
We won’t cover this much in class, so if you are not comfortable, please bone up at home.
We suggest running through the cli tutorial at “learn code the hard way”:
http://cli.learncodethehardway.org/book/
Windows:
Most of the demos in class, etc, will be done using the “bash” command line shell on OS-X. This is identical to the bash shell on Linux.
Windows provides the “DOS” command line, which is OK, but pretty old and limited, or “Power Shell” – a more modern, powerful, flexible command shell.
If you are comfortable with either of these – go for it.
If not, you can use the “git Bash” shell – which is much like the bash shell on OS-X and Linux.
The Interpreter¶
Python comes with a built-in interpreter.
You see it when you type python at the command line:
$ python
Python 3.5.0 (v3.5.0:374f501f4567, Sep 12 2015, 11:00:19)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
That last thing you see, >>> is the “Python prompt”.
This is where you type code.
Python in the Interpreter¶
Try it out:
>>> print("hello world!")
hello world!
>>> 4 + 5
9
>>> 2 ** 8 - 1
255
>>> print ("one string" + " plus another")
one string plus another
>>>
When you are in an interpreter, there are a number of tools available to you.
There is a help system:
>>> help(str)
Help on class str in module __builtin__:
class str(basestring)
| str(object='') -> string
|
| Return a nice string representation of the object.
| If the argument is a string, the return value is the same object.
...
You can type q to exit the help viewer.
You can also use the dir builtin to find out about the attributes of a
given object:
>>> bob = "this is a string"
>>> dir(bob)
['__add__', '__class__', '__contains__', '__delattr__',
'__doc__', '__eq__', '__format__', '__ge__', '__getattribute__',
'__getitem__', '__getnewargs__', '__getslice__', '__gt__',
...
'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines',
'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper',
'zfill']
>>> help(bob.rpartition)
This allows you quite a bit of latitude in exploring what Python is.
In addition to the built-in interpreter, there are several more advanced interpreters available to you.
We’ll be using one in this course called iPython
The Editor¶
Typing code in an interpreter is great for exploring.
But for anything “real”, you’ll want to save the work you are doing in a more permanent fashion.
This is where an Editor fits in.
Any good text editor will do.
MS Word is not a text editor.
Nor is TextEdit on a Mac.
Notepad is a text editor – but a crappy one.
You need a real “programmers text editor”
A text editor saves only what it shows you, with no special formatting characters hidden behind the scenes.
At a minimum, your editor should have:
- Syntax Colorization
- Automatic Indentation
In addition, great features to add include:
- Tab completion
- Code linting
- Jump-to-definition
Have an editor that does all this? Feel free to use it.
If not, we recommend SublimeText:
(Use version 3, even though it’s “beta”)
Why No IDE?¶
An IDE does not give you much that you can’t get with a good editor plus a good interpreter.
An IDE often weighs a great deal
Setting up IDEs to work with different projects can be challenging and time-consuming.
Particularly when you are first learning, you don’t want too much done for you.
Why No IDE?¶
That said... go get the educational edition of PyCharm:
https://www.jetbrains.com/pycharm-edu/
Which is awesome.