Moduli, shigo, da kuɗi (packages) yaya suke aiki?

Question

Accepted Answer

**Module** shine fili `.py` guda daya; **kuɗi** shine jerin directoris na moduli. **Shigo** yana ba ka damar yin amfani da code daga sauran moduli, dandana-dandana bangare na aiki na sake amfani da su.

## Moduli da shigo

```python
# math_utils.py — a module
def add(a, b): return a + b
PI = 3.14159
```

```python
# main.py — different ways to import
import math_utils                  # import the whole module
math_utils.add(2, 3)               # access via the module name

from math_utils import add, PI     # import specific names
add(2, 3)                          # use directly

from math_utils import add as plus # import with an alias
import numpy as np                 # common aliasing convention
```

## Kuɗi — jerin directoris na moduli

```text
mypackage/
  __init__.py        ← marks it as a package (can be empty)
  module_a.py
  subpackage/
    __init__.py
    module_b.py
```

```python
from mypackage.module_a import something
from mypackage.subpackage.module_b import other
```

Filin `__init__.py` yana nuna directory a matsayin kuɗi (kuma zai iya gudna kuɗi-init code ko bayyana abin da `from package import *` yana bayyana).

## Hadirin `if __name__ == "__main__"`

```python
def main():
    print("running as a script")

if __name__ == "__main__":   # True only when run directly, not when imported
    main()
```

Wancan ya bar fili yafiya azaman module na shigo *da* script mai aiki — code a karkashinsa yana aiki ne idan fili ya kasance a aiki kai tsaye (`python file.py`), ba lokacin da aka shigo ba. Hadirin Python kusan kowa.

## Inda Python ke neman moduli

```python
import sys
sys.path   # the list of directories Python searches for imports
# includes: the current directory, installed packages (site-packages), stdlib
```

## Standard gida da na waje

```python
import os, json, datetime    # standard library — "batteries included"
import requests              # third-party — installed via pip from PyPI
```

## Me yasa yana da mahimmanci

Moduli da kuɗi su ne yadda ka hada ma Python code cikin abubuwan da ake iya sake amfani, kyautattun gida maimakon fili guda mai girma — ainihi ne ga wani aiki da ba mai littafi ba.

Tunatarwa hadirin shigo, tsarin kuɗi (`__init__.py`), hadirin `if __name__ == "__main__"` (aiki biyu script/module), da yadda Python ke neman moduli (`sys.path`) yana da mahimmanci don yin tsarin aike, sake amfani code, da yin amfani da gida-standard library da kuma PyPI ekosistem.

Kuskure na shigo da rikicewa hadirin-hadirin abubuwan nishi ne na farko waɗanda ilimin nan ya warware.

Moduli da shigo

Kuɗi — jerin directoris na moduli

Hadirin if __name__ == "__main__"

Inda Python ke neman moduli

Standard gida da na waje

Me yasa yana da mahimmanci

Hadirin `if name == "main"`