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⭐ Importing Modules in Python

After creating a module or using a built-in module, we must import it to use the functions, variables, and classes defined inside it.

Python provides multiple ways to import modules depending on the requirement.

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⭐ 1. Basic Import Statement

Syntax

import module_name

Example

import math
print(math.sqrt(16))

✔ Fully qualifies names using module_name.function()
✔ Recommended for readability

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⭐ 2. Importing a Module with an Alias

Alias = short name for convenience.

Syntax

import module_name as alias

Example

import numpy as np
print(np.array([1,2,3]))

✔ Makes code shorter
✔ Useful for lengthy module names (e.g., numpy → np)

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⭐ 3. Importing Specific Members from a Module

To import only selected functions or variables.

Syntax

from module_name import function1, function2

Example

from math import sqrt, pi

print(sqrt(25))
print(pi)

✔ No need to prefix with module name
❌ Can cause naming conflicts if function names are common

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⭐ 4. Importing All Members of a Module (Wildcard Import)

Syntax

from module_name import *

Example

from math import *
print(sin(1))
print(cos(1))

⚠ Not recommended because:

• It imports everything, polluting the namespace
• Overwrites existing function names unknowingly

Used only when:
✔ writing small programs
✔ working interactively

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⭐ 5. Importing User-Defined Modules

If you create a file mymodule.py:

# mymodule.py
def greet(name):
    return f"Hello {name}"

Import it:

import mymodule
print(mymodule.greet("Balvinder"))

✔ Python searches for modules in the current directory first

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⭐ 6. Importing Modules from a Different Folder

If the module is in another folder, add the path:

import sys
sys.path.append("C:/myfolder")

import mymodule

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⭐ 7. Reloading a Module (When Code Changes)

When you change the module file after importing, Python does not refresh automatically.

Use:

import importlib
importlib.reload(mymodule)

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⭐ 8. Importing Inside a Function

You can also import a module within a function:

def calculate():
    import math
    return math.sqrt(16)

Used when importing module only if needed.

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⭐ How Python Finds Modules? (Module Search Path)

Python searches modules in this order:

1️⃣ Current working directory
2️⃣ PYTHONPATH environment variable
3️⃣ Installed site-packages (libraries)
4️⃣ Built-in modules

Check search locations:

import sys
print(sys.path)

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⭐ Why Multiple Import Methods?

Import Style	Use Case
import module	Best for readability; full access
import module as alias	Shortening long module names
from module import item	When using specific functions often
from module import *	Quick experimentation; NOT for production

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⭐ Exam-Ready Short Answer

Importing a module in Python means loading its functions, classes, and variables into the current program. Python provides different import styles such as: import module, import module as alias, from module import item, and from module import *. Importing improves code reusability, modularity, and allows access to built-in and user-defined functionality.

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