To remove duplicates from an array of objects in TypeScript, key them with a Map: […new Map(orders.map(o => [o.id, o])).values()] gives you one row per id, in the order they first appeared. A Set will not do it, because it compares objects by reference rather than by contents. This guide covers deduplicating by one property, … Read more >>
To sort an array in TypeScript, call sort() with a compare function: numbers.sort((a, b) => a – b) for numbers and names.sort((a, b) => a.localeCompare(b)) for text. Swap a and b for descending order. Without a compare function sort() turns every element into a string first, which is why [100, 25, 9, 1000, 3] comes … Read more >>
To check if a TypeScript array contains a specific value, call includes(): cities.includes(“Denver”) returns true or false. That works for strings, numbers and booleans. For an array of objects it will not, because includes() compares by reference, so you test a property with some() instead: orders.some(o => o.id === “ORD-1001”). This guide covers both, plus … Read more >>
To remove empty strings from an array, filter them out: values.filter(Boolean) is the short version and values.filter(value => value !== “”) is the explicit one. Both return a new array and leave the original alone. If the array also contains strings that are only spaces or tabs, trim first: values.filter(value => value.trim() !== “”). The … Read more >>
To get distinct values from an array in TypeScript, pass the array to a Set and spread it back: […new Set(arr)]. A Set keeps each value once, in first-seen order, and TypeScript keeps the element type, so a string[] stays a string[]: I compiled these snippets with TypeScript 7.0.2 running on Node.js v22.22.2. One of … Read more >>
To remove multiple keys from a dictionary in Python, loop over the keys and call d.pop(key, None) for each one. The None default means missing keys are skipped instead of raising KeyError. To keep the original intact, build a new dict with a comprehension: The examples strip private fields from US customer and order records, … Read more >>
To split an array in TypeScript, use slice(): arr.slice(0, i) gives the part before index i and arr.slice(i) gives the rest, without changing the original. To split into chunks of N items, call slice in a loop: For the outputs on this page I used TypeScript 7.0.2 on Node v22.22.2 with strict checks, so the … Read more >>
To write bytes to a file in Python, open it in binary write mode with open(path, “wb”) and call f.write(data), where data is a bytes or bytearray object. For a one-liner, Path(path).write_bytes(data) does the same: Binary mode works the same on every OS, but I ran these on Windows with Python 3.12.5, where text-mode newline … Read more >>
Python’s break and continue both change how a loop runs. break exits the loop immediately, and continue skips the rest of the current pass and moves on to the next one. Both work in for and while loops. The orders, statuses and seat numbers below are made up, but every output is real: I ran … Read more >>
pip installs a specific version when you put == and the version number after the package name. The same command downgrades or upgrades whatever’s already installed: I tested every command below in a real Windows Command Prompt with Python 3.12.5 and pip 24.2, inside a separate environment so you can see each install happen from … Read more >>