Python Operators & Type Conversion

What is an operator?

An operator is a symbol or keyword that tells Python to perform an operation on one or more values.

price = 500
quantity = 3

total = price * quantity
print(total)

Try it Yourself →

Arithmetic operators

a = 17
b = 5

print(a + b)   # addition: 22
print(a - b)   # subtraction: 12
print(a * b)   # multiplication: 85
print(a / b)   # true division: 3.4
print(a // b)  # floor division: 3
print(a % b)   # remainder: 2
print(a ** 2)  # exponent: 289

/ generally floating-point result deta hai, while // mathematical floor ki direction me round down karta hai.

Division, remainder and practical use

Floor division aur modulo together grouping, pagination aur time conversion jaise tasks me useful hote hain.

total_minutes = 135
hours = total_minutes // 60
minutes = total_minutes % 60

print(hours, "hours", minutes, "minutes")

Run division example →

Assignment operators

Compound assignment current value par operation karke name ko new result se rebind karta hai.

score = 10
score += 5
score *= 2
score -= 4

print(score)

Common forms include +=, -=, *=, /=, //=, %= and **=.

Comparison operators

Comparisons normally True or False return karte hain.

age = 21

print(age == 21)
print(age != 18)
print(age > 18)
print(age < 30)
print(age >= 21)
print(age <= 21)

Chained comparisons

Python readable chained comparisons support karta hai.

age = 25
print(18 <= age <= 60)

Ye conceptually age >= 18 and age <= 60 ke similar intent ko compact form me express karta hai.

Logical operators: and, or, not

is_logged_in = True
has_access = False

print(is_logged_in and has_access)
print(is_logged_in or has_access)
print(not is_logged_in)

and ko both sides truthy chahiye; or ko at least one truthy value; not truth value ko invert karta hai.

Short-circuit evaluation

and aur or left-to-right evaluate hote hain and result decide hote hi remaining expression skip kar sakte hain.

name = ""

display_name = name or "Guest"
print(display_name)

Membership operators: in and not in

Membership operators check karte hain ki value container me present hai ya nahi.

course = "Python"

print("Py" in course)
print("Java" not in course)

Lists, tuples, sets aur dictionaries ke saath membership ko later chapters me detail me use karenge.

Identity operators: is and is not

is equality nahi, object identity check karta hai.

value = None

print(value is None)
print(value is not None)

Operator precedence

Operators same priority se execute nahi hote. Multiplication usually addition se pehle evaluate hoti hai.

result = 2 + 3 * 4
print(result)      # 14

clear_result = (2 + 3) * 4
print(clear_result)  # 20

Complex expression me parentheses intent ko clear banate hain, even when precedence already correct ho.

What is type conversion?

Type conversion means value ko one type se another type me convert karna, when conversion meaningful and supported ho.

age_text = "21"
age = int(age_text)
price = float("199.50")
label = str(500)

print(age, type(age))
print(price, type(price))
print(label, type(label))

Try conversions →

int() and float()

int() integer-compatible input convert karta hai. float() decimal-compatible input convert karta hai.

print(int("42"))
print(float("42"))
print(int(3.9))
print(int(-3.9))

int(3.9) fractional part remove karke 3 deta hai; int(-3.9) -3 deta hai. Ye floor operation nahi, truncation toward zero hai.

str() conversion

str() value ka text representation banata hai.

score = 95
message = "Score: " + str(score)
print(message)

Python number ko string ke saath automatically concatenate nahi karta.

bool() and truthy/falsy values

bool() value ki truth value convert karta hai.

print(bool(0))
print(bool(1))
print(bool(""))
print(bool("Python"))
print(bool(None))

Common falsy values include numeric zero, empty strings/containers and None. Most other normal values truthy hote hain.

Implicit numeric conversion

Some numeric operations me Python compatible types ko automatically promote kar sakta hai.

result = 10 + 2.5
print(result)
print(type(result))

Here int and float operation produces a float. But unrelated types ke beech arbitrary implicit conversion expect mat karo.

Conversion errors

# ValueError:
# age = int("twenty")

# TypeError:
# total = "10" + 5

User input convert karte waqt invalid values possible hain. Exception handling Chapter 14 me detail me cover hoga.

Bitwise operators — brief preview

Python integers ke saath &, |, ^, ~, << and >> bitwise operators support karta hai. Beginner general application code me ye arithmetic/logical operators se less common hain, so inhe abhi recognize karna enough hai.

Common beginner mistakes

• = aur == confuse karna.
• / aur // ka difference ignore karna.
• Negative floor division ko zero-toward truncation samajhna.
• is ko value equality ke liye use karna.
• int("3.5") ko valid assume karna.
• Number aur string ko directly + se combine karna.
• Operator precedence blindly assume karna.
• and/or ko always boolean-returning samajhna.
• Invalid user input conversion errors ignore karna.

Beginner best practices

• Complex expressions me parentheses se intent clear karo.
• Value equality ke liye ==, None checks ke liye is None use karo.
• Conversion intentional rakho; data format pehle samjho.
• User input ko blindly int()/float() mat karo without considering invalid input.
• Currency/exact decimal problems me floating-point limitations yaad rakho.
• Examples ka output run karne se pehle predict karo.

Chapter checklist

• Arithmetic operators ka difference clear hai?
• /, // and % use kar sakte ho?
• Comparison and logical operators samajh aaye?
• in / not in ka purpose clear hai?
• is aur == ka difference clear hai?
• Operator precedence me parentheses kab useful hain?
• int(), float(), str(), bool() use kar sakte ho?
• Invalid conversion se error aa sakta hai ye clear hai?