#
# access a function or variable by importing an external module (file)
#

# the path name of a module reflects its directory hierarchy
import mymodule
import this.mymodule
from this import mymodule
from that import mymodule
from that.was import mymodule
import this.was.my.lib.mymodule
from this.was.my.lib import mymodule

#x import this.is.my.lib.mymodule
#x from that.is.my.lib import mymodule
#x from that.is import mymodule		# can not contains "is" in module path ???!!!

#
# and prefixing the function by module name
#
mymodule.greeting("Jonathan")

a = mymodule.person1["age"]
print('Person1 is %d years old' % a)

#
# Use a shorthand for a module name
#
#= import mymodule as mx
#x import this.is.my.lib.mymodule as mx
import this.mymodule as mx

a = mx.person1["age"]
print('Person1 is %d years old' % a)

#
# You can choose to import only parts from a module, by using the from keyword.
#

# Import only the person1 dictionary from the module:
#= from mymodule import person1
#x from this.is.my.lib.mymodule import person1
from this.mymodule import person1

# don't need to add module name as prefix
a = person1["age"]
print('Person1 is %d years old' % a)

# Note: When importing using the from keyword,
# do not use the module name when referring to elements in the module.
# Example: person1["age"], not mymodule.person1["age"]

#
# import build-in modules (located in some installation directories)
#
import platform

x = platform.system()
print('\nThe current system is %s' % x)

#
# List all the defined names belonging to the platform module:
#
#= import platform, mymodule
#x import platform, this.is.my.lib.mymodule
import platform, this.mymodule

x = dir(platform)
print("")
print('List all the defined names belonging to the platform module:', x)

#= y = dir(mymodule)
#x y = dir(this.is.my.lib.mymodule)
y = dir(this.mymodule)

print("")
print('List all the defined names belonging to the mymodule module:', y)

print("")
print('The __name__ variable for an imported module is simply its module name: %s, (NOT "__main__").' % mymodule.__name__)