Python Is Weird

If you had programmed a little bit in one or two other programming languages, and started to learn Python, you will surely notice that their something weird about its syntax.

Every programming language has its quirks, and Python is no exception. If you're coming from languages like Java, C, or JavaScript, you might find some things about Python... weird.

But don’t worry! These quirks make Python simpler and more readable once you get used to them.

Let's explore some these weird, yet interesting, aspects of the Python language. I would like you to hold this chapter deerly and come back to it from time to time.

1. No Curly Brackets {}

• In languages like C, Java, and JavaScript, curly brackets {} define blocks of code.
• Python does NOT use curly brackets. Instead, it relies on indentation to define code blocks.

JavaScript example:

if (x > 0) {
    console.log("Positive number");
}

Python equivalent:

if x > 0:
    print("Positive number")

2. Indentation Matters!

• In most languages, indentation is just for readability.
• In Python, indentation is REQUIRED! It defines the structure of your code.

Wrong Python code (no indentation):

if x > 0:
print("Positive number")  #  IndentationError: expected an indented block

Correct Python code:

if x > 0:
    print("Positive number")  #  Indented properly

3. No Semicolons ; Required

• Most languages require semicolons (;) to end statements.
• Python doesn’t need them!

JavaScript example:

console.log("Hello, World!");

Python equivalent:

print("Hello, World!")

4. def Instead of function

• In JavaScript, you define functions using function.
• In Python, you use def instead.

JavaScript function:

function greet(name) {
    return "Hello, " + name;
}

Python equivalent:

def greet(name):
    return "Hello, " + name

5. No var, let, or const – Just Assign Variables Directly!

• Python doesn’t need var, let, or const to declare variables.
• Just assign a value to a variable, and Python figures out the type automatically.

JavaScript:

let age = 25;
const name = "Alice";

Python:

age = 25
name = "Alice"

6. elif Instead of else if

• In most languages, multiple conditions use else if.
• In Python, it's elif (shorter and cleaner).

JavaScript example:

if (x > 0) {
    console.log("Positive");
} else if (x < 0) {
    console.log("Negative");
} else {
    console.log("Zero");
}

Python equivalent:

if x > 0:
    print("Positive")
elif x < 0:
    print("Negative")
else:
    print("Zero")

7. True and False Are Capitalized

• In Python, Boolean values must be written as True and False, not true or false.

JavaScript:

let isHappy = true;  // Lowercase

Python:

is_happy = True  # Uppercase

8. None Instead of null

• In many languages, a variable with no value is null.
• In Python, it’s called None (capitalized).

JavaScript:

let value = null;

Python:

value = None

9. String Formatting with f"..."

• Python has a special way to insert variables into strings using f-strings (f"...").
• This is simpler than using + or .format().

JavaScript:

let name = "Alice";
console.log("Hello, " + name + "!");

Python equivalent:

name = "Alice"
print(f"Hello, {name}!")

10. Lists Instead of Arrays

• Python doesn’t have traditional arrays like JavaScript or Java.
• Instead, it has lists, which can store different types of values.

Python list example:

numbers = [1, 2, 3, 4, 5]
mixed = [1, "hello", 3.5, True]

11. is vs == (Be Careful!)

• == checks if values are the same.
• is checks if two variables refer to the same object in memory.

Example:

x = [1, 2, 3]
y = [1, 2, 3]

print(x == y)  # ? True (values are the same)
print(x is y)  # ? False (different objects in memory)

Key Takeaways

• No curly brackets {}, indentation matters.
• No semicolons ; needed at the end of lines.
• Use def instead of function for defining functions.
• Use elif instead of else if for multiple conditions.
• Booleans are True and False, not true and false.
• Use None instead of null for empty values.
• Use f-strings (f"...") for inserting variables into strings.
• Lists ([]) replace traditional arrays.
• Be careful with is vs ==!.

Mini Challenge: Spot the Errors!

Below is a buggy Python script. Can you spot at least 3 mistakes before running it?

if (x > 0) {
    print "Positive"
} else if x < 0:
    print("Negative);
else:
    print("Zero")

Give it a try! Would you like an answer key for this challenge?