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Python does not have a classpath and unless you are root, you can't install new pkg for the whole system
# pip installs in
.local/lib/
virtualenv - solution to pkg management? - isolated space with own instance of python
virtualenv TESTENV -p python
source TESTENV/bin/activate
# to get out of env
deactivate
** exponant
x = 'Mark'
len(x) - function
x.upper() - method
dir() - built it give directory of an object (all methods available)
with no arg show you all name in global namespace
dir() == sorted(globals().keys())
gloabls() == locals()
super() - goes trought inheritance chain and return the class that is after the one passed as the function first argument. Can by used to bypass modification made by earlier classes.
# Data containers
list() - []
dict() - {}
tuple() - ()
set() - set()
__ init__ - where to assign instance specific attributes when object first constructed
__ str__ - control how object is printed
__ repr__ - object output when interactive shell
__ eq__ - uniquely identify all created object
1st time you import a modules python execute the code inside it.
2nd time will not re-run the code. (usefull when import multiples modules that import all the same modules)
importlib if want to reload modules so run more than once
When importing a module you can use it's defined functions, classes, constants etc...
Access those thing by putting the module name as prefix before the function
import X
import X as x
from X import x
from X import x as x
when you run a modules as a script __ name__ becomes __ main__
__ init__.py - required to tell python dir is a pkg (initialise a pkg) REQUIRED
used to set the __ all__ variable & import submodules
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