Variables aur Data Types

Variable bas ek naam hai jo ek value ko point karta hai. Java ya C# ke ulat, Python mein aapko pehle se type declare karne ki zaroorat nahi — bas ek value assign karo, aur Python khud samajh jaata hai type kya hai.

name = "Alice"
age = 30
height = 5.6
is_student = False

print(name, type(name))
print(age, type(age))
print(height, type(height))
print(is_student, type(is_student))

Alice <class 'str'>
30 <class 'int'>
5.6 <class 'float'>
False <class 'bool'>

Yeh hain woh chaar types jo aap baar baar use karoge: str (text), int (poore numbers), float (decimal numbers), aur bool (True ya False). type() function batata hai ki koi value actually kis type ki hai — jab confusion ho tab useful hai.

Python dynamically typed hai

Kyunki Python types ko runtime par check karta hai, pehle se declare karne ki zaroorat nahi hoti, isliye same variable name ko baad mein ek bilkul alag type mein reassign kiya ja sakta hai. Yeh convenient hai, lekin agar aap dhyan nahi rakhoge ki variable mein us waqt kya store hai, to bugs bhi aa sakte hain.

value = 10
print(value, type(value))

value = "now I am a string"
print(value, type(value))

10 <class 'int'>
now I am a string <class 'str'>

Variables ke naam kaise rakhein

• Naam mein letters, numbers, aur underscores use ho sakte hain, lekin number se start nahi ho sakta
• Python case-sensitive hai — age aur Age do alag variables hain
• Convention ke hisaab se, Python variable names snake_case use karte hain (student_name), camelCase nahi

Ek chhoti si aur kaam ki baat: Python mein ek hi line mein kai variables assign kiye ja sakte hain.

x, y, z = 1, 2, 3
print(x, y, z)

1 2 3

Aage: numbers — actual arithmetic operators aur Python int vs. float math kaise handle karta hai.