Python Fundamentals: Your First Steps in Programming

If you’re new to coding, Python is the perfect language to start with. It’s simple, powerful, and easy to understand—even if you’ve never written a single line of code before.

This guide will help you understand the basic building blocks of Python, so you can start your programming journey with confidence.

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1. Showing Output in Python

To display something on the screen in Python, we use the print() function.

print('Hello World')
print(7)
print(7.7)
print(True)

You can print multiple values too:

print('Hello', 1, 4.5, True)

Change the Separator (sep)

print('Hello', 1, 4.5, True, sep='/')  # Output: Hello/1/4.5/True

Change What Happens at the End (end)

print('hello', end='-')
print('world')  # Output: hello-world

✅ Remember: Python is case-sensitive.
❌ Writing Print() instead of print() will cause an error.

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2. Python Data Types

Python can handle many kinds of data. Here are the most common:

Core Data Types:

• Integer: Whole numbers (e.g., 5, 100)
• Float: Decimal numbers (e.g., 8.55, 1.7e309 → gives inf)
• Boolean: True or False
• String: Text (e.g., 'Hello')
• Complex: Numbers with real and imaginary parts (5 + 6j)

Collection Data Types:

• List: Ordered, changeable ([1, 2, 3])
• Tuple: Ordered, unchangeable ((1, 2, 3))
• Set: Unordered, unique values ({1, 2, 3})
• Dictionary: Key-value pairs ({'name': 'Nitish', 'age': 25})

To check the type of data, use type():

type(5)        # int
type([1, 2, 3])  # list

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3. Variables

Variables are used to store data. Python doesn’t require you to declare the type:

a = 5          # integer
a = 'hello'    # now it's a string

You can also:

a, b, c = 1, 2, 3        # multiple values
x = y = z = 10           # same value to multiple variables

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4. Comments in Python

Comments are lines that Python ignores. They help explain your code.

# This is a comment
print("Hello")  # This is also a comment

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5. Keywords and Identifiers

Keywords:

These are special words in Python like if, else, while, for. You cannot use them as variable names.

Identifiers:

These are names you give to variables or functions. Rules:

• Cannot start with a number
• Cannot use special characters like @, #, $
• Can use underscore _
• Cannot be a keyword

Valid examples:

_name = "Nitish"
name1 = "Python"

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6. Getting User Input

Use input() to get input from the user:

email = input("Enter your email: ")

All input is taken as a string. You can convert it:

a = int(input("Enter a number: "))
b = int(input("Enter another number: "))
print(a + b)

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7. Type Conversion

Implicit Conversion:

Python automatically converts one type to another:

print(5 + 5.6)  # Output: 10.6

Explicit Conversion:

Use functions to convert types:

str(5)      # '5'
float(4)    # 4.0
int("10")   # 10

TypeError:

Trying to combine incompatible types causes an error:

print(4 + '4')  # TypeError

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8. Literals in Python

Numeric Literals:

• Binary: 0b1010
• Octal: 0o310
• Hexadecimal: 0x12c
• Float: 10.5, 1.5e2, 1.5e-3
• Complex: 3.14j

z = 5 + 3j
print(z.real)  # 5.0
print(z.imag)  # 3.0

String Literals:

'hello' | "hello" | '''multi-line'''
u"\U0001f600"  # Unicode emoji
r"raw \n text"  # Backslash is not treated as escape

Boolean Literals:

True + 4   # 5
False + 10 # 10

Special Literal:

x = None

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9. Operators in Python

Python includes:

• Arithmetic (+, -, *, /)
• Relational (==, !=, <, >)
• Logical (and, or, not)
• Bitwise (&, |, ^)
• Assignment (=, +=, -=)
• Membership (in, not in)

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10. If-Else Statements

Use if-else to make decisions:

num = int(input("Enter a number: "))
if num > 0:
    print("Positive")
else:
    print("Zero or Negative")

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Conclusion

Congratulations! You just learned the most important basics of Python programming. With these concepts, you’re ready to write simple scripts and build a solid foundation for your coding journey. Keep practicing, and happy coding!

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