Phase 5 — Python-specific Features
Phase 5 — Python-specific Features
Goals for this phase, and a full JS/TS → Python cheat sheet
Estimated time: ~1.5 hours.
These don't have a clean JS/TS equivalent, but you'll see them constantly in real Python code. Don't spend hours perfecting them — the goal is just to become comfortable reading them.
Goals
By the end of this phase you should be comfortable reading:
- list comprehension
- dictionary comprehension
enumeratezip
Each topic is its own page in the sidebar, taught with a JS/TS → Python comparison, followed by a small example.
Cheat sheet
JavaScript / TypeScript Python
────────────────────────────────────────────────────────────
arr.map(x => x * x) [x * x for x in arr]
arr.filter(x => x % 2 === 0) [x for x in arr if x % 2 == 0]
.map(x => x * x) x * x
Object.fromEntries( {x: x * x for x in range(5)}
Array.from({ length: 5 },
(_, x) => [x, x * x])
)
arr.forEach((v, i) => { ... }) for i, v in enumerate(arr):
for (const [i, v] of arr.entries())
manual index loop / for a, b in zip(arr1, arr2):
lodash zip(arr1, arr2)