python assignment - 4

 python assignment - 4 

What are modules in Python?

Modules refer to a file containing Python statements and definitions.

A file containing Python code, for example: example.py, is called a module, and its module name would be example.

We use modules to break down large programs into small manageable and organized files. Furthermore, modules provide reusability of code.

We can define our most used functions in a module and import it, instead of copying their definitions into different programs.

# Python Module example

 

def add(a, b):

   """This program adds two

   numbers and return the result"""

 

   result = a + b

   return result

How to import modules in Python?

We can import the definitions inside a module to another module or the interactive interpreter in Python.

We use the import keyword to do this. To import our previously defined module example, we type the following in the Python prompt.

>>> import example

This does not import the names of the functions defined in example directly in the current symbol table. It only imports the module name example there.

Using the module name we can access the function using the dot . operator. For example:

>>> example.add(4,5.5)

9.5

Python has tons of standard modules. You can check out the full list of Python standard modules and their use cases. These files are in the Lib directory inside the location where you installed Python.

Standard modules can be imported the same way as we import our user-defined modules.

There are various ways to import modules. They are listed below..

---

Python import statement

We can import a module using the import statement and access the definitions inside it using the dot operator as described above. Here is an example.

# import statement example

# to import standard module math

import math

print("The value of pi is", math.pi)

When you run the program, the output will be:

The value of pi is 3.141592653589793

---

Import with renaming

We can import a module by renaming it as follows:

# import module by renaming it

import math as m

print("The value of pi is", m.pi)

We have renamed the math module as m. This can save us typing time in some cases.

Note that the name math is not recognized in our scope. Hence, math.pi is invalid, and m.pi is the correct implementation.

---

Python from...import statement

We can import specific names from a module without importing the module as a whole. Here is an example.

# import only pi from math module

from math import pi

print("The value of pi is", pi)

Here, we imported only the pi attribute from the math module.

In such cases, we don't use the dot operator. We can also import multiple attributes as follows:

>>> from math import pi, e

>>> pi

3.141592653589793

>>> e

2.718281828459045

------------------------------------------------------------------------------------

2 . question answer's  )

.dic1={1:10, 2:20}
dic2={3:30, 4:40}
dic3={5:50,6:60}
dic4 = {}
for d in (dic1, dic2, dic3): dic4.update(d)
print(dic4)