Syntax Basics

Python syntax will feel weird for exactly one day — then it clicks. Five ideas, one reel.

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What you'll learn

Dynamic typing
Indentation & blocks
f-strings & formatting
None & truthiness
Operators & ranges

Remember this

Variables are name tags — untyped, movable, runtime-checked
Indentation IS the block structure — 4 spaces, no braces
f-strings interpolate anything; falsy = None/0/empty; use is None

Dynamic typing

x = 5 — no type declaration. Variables are names bound to objects.
Rebinding to another type is legal; errors appear at runtime (type hints + mypy fix this — Reel PY-08).

Indentation & blocks

Whitespace is syntax: indent = enter block, dedent = exit block.
4 spaces per level (PEP 8); set the editor to convert tabs.
Everything in a block must be indented — even single statements.

f-strings

f"Total: {price:.2f}"      # format spec inside braces
f"{n:,}"                   # thousands separators
f"{name.upper()} ok"       # any expression

None & truthiness

None = absence of a value (like null). Check with is None.

Falsy	Truthy
`None`, `False`, `0`, `""`, `[]`, `{}`, `()`	everything else

Operators

== value equality · is identity (same object) · in membership.
range(5) → lazy sequence 0..4; list(range(5)) materializes it.
for i in range(n): replaces C-style index loops in most cases.

Code: Syntax basics in 20 lines

# Dynamic typing — name tags, not declarations
price = 19.99
label = "pro"
price = label          # legal! the tag moves to a string

# Indentation is the block
if price == "pro":
    print("Pro plan")
    print("  unlimited reels")
print("always runs")   # dedented → outside the if

# f-strings: interpolation + formatting
rows = 1_234_567
print(f"Imported {rows:,} rows in {0.847:.2f}s")

# Truthiness
items = []
if not items:          # same as: if len(items) == 0
    print("empty list is falsy")

if price is None:
    pass               # explicit None check with `is`

# in + range
for i in range(3):     # 0, 1, 2
    if "pro" in label:
        print(f"  step {i + 1} of 3")