Syntax — Python's Whitespace Grammar

The file is just code

Coming from PHP, the first relief is that there's no <?php tag. A .py file is code from the first byte. You run it with python script.py, or you type lines into a notebook cell. No "enter code mode" ceremony.

🐘 PHP: PHP needs the opening tag because it was born to sprinkle code into HTML. Python was born as a general scripting language, so the whole file is the program. No tag to forget at 1am.

Indentation IS the block

This is the headline. Where PHP and JavaScript use { } to group statements, Python uses indentation. The colon opens a block; the indented lines underneath are the block; dedenting closes it.

if revenue > target:
    print("Above target")
    bonus = revenue * 0.1
print("Always runs")   # back at the left margin = outside the if

Pick four spaces per level and never look back — it's the universal convention, and notebooks/editors insert it for you when you press Tab. The one hard rule: don't mix tabs and spaces in the same file. Python will throw a TabError and you'll lose ten minutes to something invisible. Modern editors prevent this if you let them insert spaces for Tab.

🐘 PHP: In PHP, indentation is purely cosmetic — the braces do the real work, and you could write a whole function on one line. In Python the indentation is the braces. It feels strict for a day, then you realise every Python file on earth is formatted consistently because the language forces it. That's a gift when you read other people's code.

Variables — no dollar sign, no declaration

count = 0
name = "Eric"
is_enrolled = True
tags = ["python", "data", "ba"]

A variable exists the moment you assign to it. No $, no var/let, no type keyword. The naming convention is snake_case for variables and functions, PascalCase for classes, SCREAMING_SNAKE for constants — identical to the PHP conventions you already use, just without the prefix.

🐘 PHP: $name = "Eric"; becomes name = "Eric". Drop the dollar, drop the semicolon. The dollar sign's one perk — variables standing out visually — is gone, so lean on good names instead.

No semicolons (and no, you don't need them)

A newline ends a statement. You can put a semicolon between two statements on one line, but it's considered ugly and you'll almost never see it. One statement, one line.

x = 5
print(x)

If a single expression genuinely needs to span multiple lines, wrap it in parentheses and Python reads across the line breaks happily — no backslash gymnastics required:

total = (
    base_price
    + tax
    + shipping
)

Printing and the f-string

print() is your output workhorse — think echo, but it's a function so it takes parentheses. The modern way to build strings with values baked in is the f-string: put f before the quotes and drop variables inside { }.

name = "Eric"
revenue = 1800
print(f"Hello, {name}. Revenue is ${revenue:,}.")
# Hello, Eric. Revenue is $1,800.

That :, inside the braces is a format spec — here it adds thousands separators, which you'll use constantly in financial reporting. F-strings are clean, fast, and the default choice; reach for them every time.

🐘 PHP: An f-string is exactly PHP's double-quoted interpolation ("Hello, $name") but more powerful, because the { } can hold any expression and a format spec. Plain string literals without the f are like PHP single quotes — literal, no substitution.

Comments and the docstring

# single-line comment, the only everyday kind

"""
Triple-quoted string. Used as a multi-line note, and
as a function's official documentation (a 'docstring').
"""

Python has just one comment marker: #. The triple-quoted string pulls double duty as multi-line notes and as documentation that tools can read. As in PHP, comment the why, not the obvious what.

Case sensitivity — consistent, unlike PHP

Good news: Python is case-sensitive everywhere, with no exceptions. Revenue, revenue, and REVENUE are three different names, full stop — for variables, functions, and classes alike. No "functions are case-insensitive but variables aren't" surprises. One rule, applied uniformly.

🐘 PHP: Remember PHP's quirk where strlen() and STRLEN() both work but $Name ≠ $name? Python doesn't have that split personality. Everything is case-sensitive, so just stay in lowercase snake_case and you'll never trip.