🐍 Imports

imports

Good to know

⭐️ Importing lets you reuse code from other files, modules, or libraries. You can import whole modules, specific functions, or entire classes. Imports happen at the top of a file by convention. Note: When you import a module, Python executes that module’s top-level code once, and then caches it.

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Importing a Full Module

Imports everything inside the module and accesses it with the module name.

import math
 
print(math.sqrt(16))

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Importing Specific Functions or Classes

Avoids having to prefix with the module name.

from math import sqrt
 
print(sqrt(16))

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Importing Multiple Items

from math import sqrt, ceil, floor

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Importing With an Alias

Useful for shortening long module names.

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

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Importing Everything (Not Recommended)

This can overwrite names and make debugging harder.

from math import *

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Importing Your Own Python Files (Modules)

Any .py file is a module you can import. Ensure both files are in the same folder or Python path.

# file: helpers.py
def greet():
    print("Hello!")

# file: main.py
import helpers
 
helpers.greet()

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Importing Classes From Another File

# file: dog.py
class Dog:
    def bark(self):
        print("Woof!")

# file: main.py
from dog import Dog
 
d = Dog()
d.bark()

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Importing a Module Inside a Folder (Package)

Folders with an init.py file are considered packages.

project/
├── animals/
│   ├── __init__.py
│   └── dog.py
└── main.py

# main.py
from animals.dog import Dog

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Relative Imports (Inside Packages)

Useful when modules live in the same package.

from .dog import Dog
from ..utils import helper_function

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Checking Installed Modules

import sys
print(sys.modules)