Menene bambanci tsakanin abubuwan da za a iya canzawa da waɗanda ba za a iya canzawa?

Question

Accepted Answer

**Abubuwan da ba za a iya canzawa** ba za a iya canzawa bayan haɗawa; **abubuwan da za a iya canzawa** za a iya canzawa. Wannan bambanci ya kasance mahali na cibiyar Python kuma yana shafar aliasing, maɓallan dict, munaye na aiki, da nau'in ɗimikun ƙanuka.

## Sassan biyu

```text
Immutable: int, float, bool, str, tuple, frozenset, bytes, None
Mutable:   list, dict, set, bytearray, and most custom objects
```

## Ba za a iya canzawa: "canzawa" yana haɗa sabon abu

```python
x = "hello"
x.upper()       # returns a NEW string "HELLO" — x is unchanged
x += " world"   # rebinds x to a NEW string; the original "hello" is untouched

n = 5
n += 1          # creates a new int 6; doesn't modify the int object 5
```

Tare da waɗanda ba za a iya canzawa, ayyuka waɗanda suke kama "canzawa" na ƙimar ga gaske sun haɓaka sabon abu kuma sun sake mahali mai ƙarfi. Ba a taɓa canza gida.

## Za a iya canzawa: canzewa a waje

```python
lst = [1, 2, 3]
lst.append(4)   # modifies the SAME list object → [1, 2, 3, 4]
lst[0] = 99     # in-place change
```

## Taɓin aliasing (hadarin da ake buƙata)

```python
# mutable — two names point to the SAME object
a = [1, 2, 3]
b = a            # b is NOT a copy — it's the same list
b.append(4)
print(a)         # [1, 2, 3, 4] ← a changed too! (they're aliases)

# to actually copy:
b = a.copy()     # or list(a), or a[:]
```

Aikawa abu da za a iya canzawa bai kunna shi ba — sunaye biyu suna yin aiki ga abu gida, don haka canzewa ta hanyar gida yana shafar waje. Wannan ya dace da da yawa kuma yana haɗa kyau bugs.

## Me ya sa ba za a iya canzawa za su iya zama dict keys / set members

```python
d = {(1, 2): "point"}   # ✅ tuple key — immutable, hashable
d = {[1, 2]: "x"}       # ❌ TypeError — lists are unhashable (mutable)
```

Dict keys da set members dole ne su kasance **hashable**, wanda ya nanaɗi ba za a iya canzawa (mad key na iya canzawa zai iya canza kuma ya ɓata teburin hash).

## Munaye na aiki

```python
def modify(lst): lst.append(99)   # mutates the caller's list (passed by reference)
def rebind(n): n += 1             # rebinds locally; caller's int unchanged
```

## Me ya sa yana matukaici

Aikawar canzawa abin da ba za a iya canzawa ne mahali na cibiyar Python wanda ya bayyana jerin haɗis da ɗimikun: taɓin aliasing (aikawa bai kunna abubuwan da za a iya canzawa ba), me ya sa aiyuka za su iya canzawa lissafi ana watse ba int, me ya sa abubuwan da ba za a iya canzawa kaɗai za su iya zama dict keys/set members, da aikawar default argument na iya canzawa.

Sanin waɗanne nau'ikan da za a iya canzawa vs ba za a iya canzawa — kuma cewa canzewa abu da aka raba yana shafar duk tunawa shi — shine mahali a cikin rubuta Python dai kuma don kare wasu washe-washen da aka fi sani.