Print

The print() function writes output to the screen. Pass it multiple values separated by commas and Python prints them with a space between each one by default.

print("ByteWise", "Ultimate")

Two optional keyword arguments give you more control: sep changes what's inserted between values, and end changes what's printed after the last one (a newline, "\n", by default).

print("ByteWise", "Ultimate", sep=" | ")
print("Loading", end="...")
print("done")

Keywords & Identifiers

Keywords are reserved words built into Python's grammar. You can't use them as variable names because they already have a special meaning. Some of the most common ones:

• if, elif, else — conditional statements
• for, while — loops
• def, return — defining and exiting functions
• True, False, None — the only built-in keywords that start with a capital letter
• and, or, not, in, is — logical, membership, and identity operators
• break, continue, pass — loop control
• try, except, finally — exception handling

Identifiers are the names you choose for variables, functions, and everything else. A few rules keep them valid:

• Must start with a letter or an underscore — never a digit
• Can contain letters, digits, and underscores after that first character
• No spaces or other special characters allowed
• Can't be a keyword
• Case-sensitive — age and Age are different variables

user_name = "ByteWise"    # valid
_score = 100              # valid, starts with an underscore
2nd_place = "silver"      # invalid - starts with a digit
class = "example"         # invalid - 'class' is a keyword

Blocks & Indentation

Instead of curly braces, Python uses indentation to mark where a block of code starts and ends. The convention is 4 spaces per level. Every colon-terminated line — if, for, while, def, and more — opens a new indented block underneath it.

def square_all(n):
    for i in range(n):
        result = i ** 2
        print(result)

square_all(4)

Mixing tabs and spaces, or indenting inconsistently, raises an IndentationError. Python is strict about this on purpose — indentation always reflects the real structure of your code.

Operators

Operators combine values into new ones. Python groups them into a few families.

Arithmetic — do the math you'd expect, with two small surprises: / always returns a float, even on an exact division, and // (floor division) returns a float too if either operand is already a float.

print(6 / 2)
print(7 // 2)
print(6.5 // 2)
print(17 % 6)

Relational — compare two values and return a bool. Strings are compared character by character using their underlying character codes, not their length.

print(3 == 3)
print("a" > "z")
print("Bro" < "x")

Logical — combine boolean expressions. and needs both sides True, or needs at least one, and not flips the result.

a = 3 > 4
b = 0 != 1
print(a and b)
print(a or b)
print(not b)

Assignment — = assigns a value. The augmented forms (+=, -=, *=, /=, //=, %=, **=) update a variable using its current value in one step.

a = 16
a += 5
a -= 5
a *= 2
print(a)

Identity & Membership — is / is not check whether two names point to the exact same object in memory, a different question from whether they're equal (==). in / not in check whether a value exists inside a sequence.

s1 = "ByteWise"
s2 = "ByteWise"
print(s1 == s2)
print(s1 is s2)
print("Byte" in s1)

Comments

Comments are notes for humans — Python ignores them completely when running the code. A single-line comment starts with #. For notes spanning multiple lines, wrap them in triple quotes.

# This explains what the next line does
total = price * quantity   # inline comments work too

"""
This is a multi-line comment.
Useful for longer explanations.
"""

Input

input() pauses the program and waits for the user to type something and press Enter. Whatever they type always comes back as a string — even if it looks like a number — so you need to convert it explicitly to do math with it.

name = input("Enter your name: ")
print(name, type(name))

Trying to add a raw input straight to a number raises a TypeError, because you'd be mixing a string with an int:

age = input("Enter age: ")
print(age + 10)

Wrapping the input in int() fixes it:

age = int(input("Enter age: "))
print(age + 10)