#!/usr/bin/env python
# coding: utf-8

# # Modules
# - module is a file containing Python definitions and statements intended for use in other Python programs
# - many Python modules come with built-in standard library

# ## Various ways to import names into the current namespace

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# import math module into the global namespace
import math
x = math.sqrt(100)
print(x)


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import random
print(random.choice(list(range(1, 21))))


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from random import choice


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print(choice([1, 2, 3, 4]))


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help(math)


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from math import * # Import all the identifiers from math
print(sqrt(100))
print(pi)


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from math import radians, sin
rad = radians(90)
print(rad)
print(sin(rad))


# ## names can be imported to local namespace

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def isUpper(letter):
    import string # string name is local
    return letter in string.ascii_uppercase


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print(isUpper('a'))


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# can we use string module outside isUpper function?
print(string.digits)


# ## scope and lookup rules
# <p>The <strong>scope</strong> of an identifier is the region of program code in which the identifier can be accessed, or used.</p>
# Three important scopes in Python:
# - <strong> Local scope </strong> refers to identifiers declared within a function
# - <strong>Global scope</strong> refers to all the identifiers declared within the current module, or file
# - <strong>Built-in scope</strong> refers to all the identifiers built into Python -- those like <em>range</em> and <em>min</em> that are (almost) always available 
# <p>Precedence rule:</p>
# <ol>
#     <li>innermost or local scope</li>
#     <li>global scope</li>
#     <li>built-in scope</li>
# </ol>

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def testLocalScope():
    k = 5
    for i in range(2):
        for j in range(2):
            if i == j:
                k = 3
                print('inside=',k)
    print('outside=',k)


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test()


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print(k)


# ## User-defined modules
# #### use module1.py, module2.py inside modules folder to demonstrate user defined modules and importance of:
# ```if __name__ == '__main__':
#         ...
# ```

# # Packages
# - folder with module(s)
# - must define \__init\__.py empty module to initialize as package
# - can't import package itself (in a useful way) but only module(s) or identifiers in the modules
# - https://docs.python.org/3/tutorial/modules.html#packages

# ## use fibos package to demostrate user-defined package

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import fibos


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help(fibos)


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fibos.fibo.fib(10)


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import fibos.fibo as f
f.fib(10)


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from fibos import fibo
fibo.fib(10)


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