{"id":216,"date":"2019-12-26T23:21:00","date_gmt":"2019-12-26T23:21:00","guid":{"rendered":"https:\/\/zofxare.com\/zofxare\/blog\/2019\/12\/26\/python-tutorial-series-modules\/"},"modified":"2019-12-26T23:21:00","modified_gmt":"2019-12-26T23:21:00","slug":"python-tutorial-series-modules","status":"publish","type":"post","link":"https:\/\/zofxare.com\/zofxare\/blog\/2019\/12\/26\/python-tutorial-series-modules\/","title":{"rendered":"Python Tutorial Series – Modules"},"content":{"rendered":"

A Python module is composed of the classes, functions and variables contained in a single python file. A python file can contain multiple classes, not just a single class like in Java. Module names should be simple and ideally kept to one word.<\/p>\n

Below is an example module, which is contained in a file called mod.py:
\nNote: The module name is the name of the file minus the .py extension.<\/p>\n

<\/pre>\n
\nONE = 1<\/p>\n
def do_something():
\n  print(‘I am a function that does something’)<\/p>\n
class Class1:
\n  def __init__(self, a):
\n    self.a = a<\/p>\n
  def printa(self):
\n    print(self.a)<\/p>\n
\nModules are imported as follows:<\/p>\n
<\/pre>\n
\nimport mod<\/p>\n
\nThis imports mod into the current symbol table, not everything inside mod. Everything inside mod is accessible though.<\/p>\n
Modules may also be imported using a shortcut for the module name:<\/p>\n
<\/pre>\n
\nimport mod as m<\/p>\n
\nIndividual names may be imported into the current symbol table as follows:<\/p>\n
<\/pre>\n
\nfrom mod import Class1<\/p>\n
\nThis does not import mod into the symbol table though, only Class1.<\/p>\n
Names may also be imported using:<\/p>\n
<\/pre>\n
\nfrom mod import *<\/p>\n
\nHowever, this method is not recommended as it’s introducing unknown names and could override something already defined.<\/p>\n
If a module member is frequently used, it can be assigned to a variable to shorten things up as follows:<\/p>\n
<\/pre>\n
\nimport mod<\/p>\n
do = mod.do_something()
\ndo()<\/p>\n
\nThis would also work:<\/p>\n
<\/pre>\n
\nfrom mod import do_something as do<\/p>\n
do()<\/p>\n
The example mod module could be used by another file, main.py, as follows:<\/p>\n
<\/pre>\n
\nimport mod<\/p>\n
mod.do_something()
\nprint(mod.ONE)<\/p>\n
clazz = mod.Class1(5)
\nclazz.printa()<\/p>\n
Modules should be well organized and contain classes, functions and variables which make sense being grouped together. I’m not a big fan of super large files. Since there is not a restriction on how many classes can be defined in a single file, a file could get large quickly. If a class, function, or the module itself, is pretty large, it could be a sign there’s too much going on and may be able to be broken down further into smaller pieces.<\/p>\n
More Python<\/a><\/p>\n