Fayl I/O (kirish/chiqish)

Bu bo'lim Python 3'dagi asosiy kirish/chiqish (I/O) amallarini qamrab oladi — ekranga chiqarish, klaviaturadan ma'lumot olish va diskdagi fayllar bilan ishlash.

print() bilan chiqarish

print() qiymatlarni matnga aylantiradi va standart chiqishga yozadi.

print("Python is a great programming language")
print("A", "B", "C", sep="-")

input() bilan klaviaturadan kiritish

Python 3'da input() har doim satr qaytaradi.

# Odatda input() dan keladigan qiymatlarni simulyatsiya qilamiz
name = "Alice"
age = 24
print(f"Hello {name}, next year you are {age + 1}")

Faylni ochish

Hammasi o'rnatilgan (built-in) open() funksiyasidan boshlanadi. U fayl yo'lini va nima qilmoqchi ekaningizni bildiruvchi rejimni (mode) oladi hamda fayl obyektini qaytaradi.

f = open("notes.txt", "w", encoding="utf-8")
f.write("learn python\n")
f.close()   # ochgan narsangizni doim yoping

Matn fayllari uchun har doim encoding="utf-8" bering, shunda kodingiz har bir operatsion tizimda bir xil ishlaydi.

Fayl rejimlari

with operatori (tavsiya etiladi)

Fayl ish tugagach har doim yopilishi kerak. with operatori uni siz uchun avtomatik yopadi — hatto blok ichida xato yuz bersa ham — shuning uchun close()'ni o'zingiz chaqirishingiz shart emas.

with open("notes.txt", "w", encoding="utf-8") as f:
    f.write("learn python\n")
    f.write("File I/O is important\n")
# fayl bu yerda avtomatik yopiladi

Fayllarni o'qish

Matnni o'qishning bir nechta usuli bor — hammasini birdan yoki qatorma-qator olishingizga qarab.

with open("notes.txt", "r", encoding="utf-8") as f:
    content = f.read()        # butun fayl bitta satr sifatida
    print(content)

Asosiy o'qish metodlari:

• read() → butun fayl satr sifatida
• read(n) → birinchi n ta belgi
• readline() → bitta qator (oxiridagi yangi qator belgisi bilan)
• readlines() → har bir elementi bitta qator bo'lgan ro'yxat

with open("notes.txt", "r", encoding="utf-8") as f:
    first = f.readline()
    print("First line:", first.strip())

with open("notes.txt", "r", encoding="utf-8") as f:
    lines = f.readlines()
    print("Number of lines:", len(lines))

Fayl bo'ylab aylanish

Faylni qayta ishlashning eng toza va xotira uchun eng qulay usuli — uni to'g'ridan-to'g'ri aylanib chiqish. U bir vaqtning o'zida bitta qatorni o'qiydi, bu hatto juda katta fayllar uchun ham ishlaydi.

with open("notes.txt", "r", encoding="utf-8") as f:
    for line in f:
        print(line.strip())

Yozish va qo'shish

"w" bilan ochish faylning ustiga yozadi; "a" mavjud kontentni saqlab, oxiriga qo'shadi. Satrlar ro'yxatini yozish uchun writelines() ishlating.

# Ustiga yozish
with open("notes.txt", "w", encoding="utf-8") as f:
    f.write("line 1\n")

# Qo'shish
with open("notes.txt", "a", encoding="utf-8") as f:
    f.writelines(["line 2\n", "line 3\n"])

with open("notes.txt", "r", encoding="utf-8") as f:
    print(f.read())

Binar fayllar bilan ishlash

Xom baytlarni o'qish yoki yozish uchun rejimga "b" qo'shing — rasmlar, audio yoki istalgan matnsiz fayl uchun. Binar rejimda siz str emas, bytes bilan ishlaysiz.

data = bytes([80, 121])   # "Py" uchun baytlar

with open("data.bin", "wb") as f:
    f.write(data)

with open("data.bin", "rb") as f:
    print(f.read())   # b'Py'

Fayllarni tekshirish va o'chirish

os va pathlib modullari faylning mavjudligini tekshirish, hajmini olish va uni o'chirish imkonini beradi.

import os

with open("temp.txt", "w", encoding="utf-8") as f:
    f.write("temporary\n")

print(os.path.exists("temp.txt"))   # True
print(os.path.getsize("temp.txt"))  # bayt hajmi

os.remove("temp.txt")
print(os.path.exists("temp.txt"))   # False

Zamonaviy pathlib API'si shu amallarni obyektga yo'naltirilgan uslubda taklif etadi:

from pathlib import Path

path = Path("greeting.txt")
path.write_text("Hello from pathlib\n", encoding="utf-8")

print(path.read_text(encoding="utf-8"))
print(path.exists())   # True

path.unlink()          # faylni o'chirish

Xavfsiz JSON I/O misoli

import json

data = {"name": "Alice", "level": "intermediate"}

with open("user.json", "w", encoding="utf-8") as f:
    json.dump(data, f, ensure_ascii=False, indent=2)

with open("user.json", "r", encoding="utf-8") as f:
    loaded = json.load(f)

print(loaded)