Python Language Importing modules Importing a module
Example
Use the import statement:
>>> import random
>>> print(random.randint(1, 10))
4
import module will import a module and then allow you to reference its objects -- values, functions and classes, for example -- using the module.name syntax. In the above example, the random module is imported, which contains the randint function. So by importing random you can call randint with random.randint.
You can import a module and assign it to a different name:
>>> import random as rn
>>> print(rn.randint(1, 10))
4
If your python file main.py is in the same folder as custom.py. You can import it like this:
import custom
It is also possible to import a function from a module:
>>> from math import sin
>>> sin(1)
0.8414709848078965
To import specific functions deeper down into a module, the dot operator may be used only on the left side of the import keyword:
from urllib.request import urlopen
In python, we have two ways to call function from top level. One is import and another is from. We should use import when we have a possibility of name collision. Suppose we have hello.py file and world.py files having same function named function. Then import statement will work good.
from hello import function
from world import function
function() #world's function will be invoked. Not hello's
In general import will provide you a namespace.
import hello
import world
hello.function() # exclusively hello's function will be invoked
world.function() # exclusively world's function will be invoked
But if you are sure enough, in your whole project there is no way having same function name you should use from statement
Multiple imports can be made on the same line:
>>> # Multiple modules
>>> import time, sockets, random
>>> # Multiple functions
>>> from math import sin, cos, tan
>>> # Multiple constants
>>> from math import pi, e
>>> print(pi)
3.141592653589793
>>> print(cos(45))
0.5253219888177297
>>> print(time.time())
1482807222.7240417
The keywords and syntax shown above can also be used in combinations:
>>> from urllib.request import urlopen as geturl, pathname2url as path2url, getproxies
>>> from math import factorial as fact, gamma, atan as arctan
>>> import random.randint, time, sys
>>> print(time.time())
1482807222.7240417
>>> print(arctan(60))
1.554131203080956
>>> filepath = "/dogs/jumping poodle (december).png"
>>> print(path2url(filepath))
/dogs/jumping%20poodle%20%28december%29.png
