Variables aur Data Types

Variable bas ek naam hai jo ek value ki taraf ishara karta hai. Java ya C# ke bar-aks, 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 istemal karoge: str (text), int (poore numbers), float (decimal numbers), aur bool (True ya False). type() function batata hai ke koi value asal mein kis type ki hai — jab confusion ho tab kaam aata hai.

Python dynamically typed hai

Kyunke Python types ko runtime par check karta hai, pehle se declare karne ki zaroorat nahi hoti, isliye ek hi variable naam ko baad mein bilkul alag type mein reassign kiya ja sakta hai. Yeh sahulat wali baat hai, lekin agar aap dhyan nahi rakhoge ke 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 istemal ho sakte hain, lekin number se shuru nahi ho sakta
• Python case-sensitive hai — age aur Age do alag variables hain
• Convention ke mutabiq, Python variable names snake_case istemal karte hain (student_name), camelCase nahi

Ek chhoti si magar 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 — asal arithmetic operators aur Python int vs. float math kaise handle karta hai.