Core Python

🔢 Data Types

Data Type	Description	Pros	Example (Pro)	Cons	Example (Con)
int	Integer numbers (e.g., 1, 42, -5)	Fast operations	Arithmetic like 1000 * 1000 runs quickly	Limited by memory	Very large ints use more memory: 10**1000
float	Decimal numbers (e.g., 3.14, -0.01)	Precise for many cases	0.1 + 0.2 appears fine in simple math	Rounding/precision issues	0.1 + 0.2 == 0.3 → False due to binary float representation
str	Text data ("hello", 'world')	Rich methods, Unicode support	"abc".upper() → 'ABC'	Immutable	"abc"[0] = 'x' → Error
bool	Logical values (True, False)	Clear for control flow	Used in if, while for readability	Only two values	Can't represent uncertainty beyond True/False
list	Ordered, mutable sequence ([1, 2, 3])	Flexible, powerful methods	append, pop, slicing	Slower lookup than dict/set	5 in large_list is O(n)
tuple	Ordered, immutable sequence ((1, 2, 3))	Safer (can't be modified)	Useful as dict keys: {(1,2): 'a'}	Immutable	Can't append or remove
set	Unordered unique items ({1, 2, 3})	Fast membership testing	x in my_set is O(1)	No indexing/order	my_set[0] → Error
dict	Key-value store ({'a': 1})	Fast key-based lookup	my_dict['name'] is fast	Keys must be unique	Duplicate keys overwrite: {'a': 1, 'a': 2} → {'a': 2}

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🔄 Type Casting (Type Conversion)

Type Cast	Description	Pros	Example (Pro)	Cons	Example (Con)
int()	Converts to integer	Removes decimal points	int(3.9) → 3	Loses precision	int(9.99) → 9
float()	Converts to float	Adds precision	float(5) → 5.0	Can lead to rounding issues	float("3.14") + 1e-16 may not be 3.1400000000000001
str()	Converts to string	Useful for printing/logs	str(123) → '123'	Not usable in math ops	'10' + 5 → TypeError
bool()	Converts to Boolean	Helps in logical filtering	bool([]) → False	Can be confusing	bool("False") → True
list()	Converts to list	Good for iterables	list("abc") → ['a', 'b', 'c']	Can create large lists	list(range(1_000_000)) → High memory usage
set()	Converts to set	Removes duplicates	set([1,2,2,3]) → {1,2,3}	Unordered result	No guarantee of element order
tuple()	Converts to tuple	Immutable, hashable	tuple([1,2,3]) → (1,2,3)	Can't modify	my_tuple[0] = 9 → Error

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➕ Operators

🧮 Arithmetic Operators

Operator	Description	Example	Notes
+	Addition	2 + 3 → 5	Works on numbers and strings ('a' + 'b')
-	Subtraction	5 - 2 → 3
*	Multiplication	3 * 4 → 12	Also works for string repetition: 'a' * 3 → 'aaa'
/	Division	7 / 2 → 3.5	Always returns float
//	Floor Division	7 // 2 → 3	Rounds down
%	Modulus	7 % 2 → 1	Remainder
**	Exponentiation	2 ** 3 → 8	Power of a number

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🔍 Comparison

Operator	Description	Example
==	Equal	5 == 5 → True
!=	Not Equal	5 != 3 → True
>	Greater than	5 > 3 → True
<	Less than	3 < 5 → True
>=	Greater or equal	5 >= 5 → True
<=	Less or equal	4 <= 5 → True

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🔗 Logical

Operator	Description	Example
and	True if both are true	True and True → True
or	True if at least one is true	True or False → True
not	Negation	not True → False

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📦 Assignment

Operator	Description	Example	Notes
is	Same object identity	a is b	Compares memory addresses
is not	Not same identity	a is not b	Use with caution for numbers/strings (interning)

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🧪 Identity & Membership

Operator	Description	Example
in	Checks if element is in sequence	'a' in 'cat' → True
not in	Checks if element is NOT in sequence	5 not in [1,2,3] → True