“Arrays” in Information Technology

117 questions across 10 technologies.

Information Technology

117 questions in 10 technologies

#	Question	Technology	Topic	Level
1	What is an array in PHP and what types of arrays does PHP support? PHP › Arrays in PHP	PHP	Arrays in PHP	Beginner
2	How do multidimensional arrays work in Java, and how do they differ from truly rectangular arrays in languages like C? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Intermediate
3	What utility methods does java.util.Arrays provide for common array operations like sorting, searching, filling, and comparing? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Intermediate
4	How do you convert between an array and a List (ArrayList) in both directions, and what pitfalls exist with Arrays.asList()? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Intermediate
5	What is array covariance's relationship to generic arrays, and why can't you directly create a generic array like new T[10] or new List<String>[10]? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Intermediate
6	How do you sort arrays in PHP, and what is the difference between functions like sort, asort, and usort? PHP › Arrays in PHP	PHP	Arrays in PHP	Intermediate
7	Why can array holes (sparse arrays) behave unexpectedly with iteration methods? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Advanced
8	How does Java implement covariant array typing, and why is this considered a design flaw that can lead to runtime ArrayStoreException? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Advanced
9	How would you efficiently copy, resize, or merge large arrays in Java, and what are the performance trade-offs between System.arraycopy(), Arrays.copyOf(), and manual loops? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Advanced
10	How does the JVM lay out array objects in memory, including the array header overhead, and how does this affect memory efficiency for very large arrays of primitives versus boxed wrapper types? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Advanced
11	How do you merge, combine, and compare arrays in PHP, and what are the subtle differences between array_merge and the plus operator? PHP › Arrays in PHP	PHP	Arrays in PHP	Advanced
12	How does PHP handle array copying behavior, and when do arrays actually get passed by reference instead of by value? PHP › Arrays in PHP	PHP	Arrays in PHP	Advanced
13	How do C# 12's collection expressions (`[1, 2, 3]`) provide a unified, type-agnostic syntax for initializing arrays, lists, and spans? C# › Modern C# Features (Global Usings, File-Scoped Namespaces, Top-Level Statements)	C#	Modern C# Features (Global Usings, File-Scoped Namespaces, Top-Level Statements)	Advanced
14	How do generics interact with arrays, and why does the JDK itself sometimes use an unsafe cast (like in ArrayList's internal implementation) to work around the inability to create generic arrays directly? Java › Generics	Java	Generics	Advanced
15	How does variance (covariance, contravariance, invariance) apply differently to Java arrays versus Java generics, and what practical safety trade-off does this design difference represent? Java › Generics	Java	Generics	Advanced
16	What are the limitations of PHP generators compared to regular arrays, particularly around rewinding and multiple iteration passes? PHP › Generators & Iterators	PHP	Generators & Iterators	Advanced
17	What is the difference between the 'include'/'exclude' arrays and the 'files' array in tsconfig.json for specifying which files are part of the compilation? TypeScript › tsconfig & Compiler Options	TypeScript	tsconfig & Compiler Options	Intermediate
18	How do you work with arrays within a JSON document stored in Redis, such as adding a new item to an existing array? Redis › RedisJSON	Redis	RedisJSON	Intermediate
19	How do you destructure nested objects and arrays in one statement? JavaScript › Destructuring, Spread & Rest	JavaScript	Destructuring, Spread & Rest	Advanced
20	What's the performance and memory advantage of a generator-based lazy pipeline over building intermediate arrays with map/filter? JavaScript › Iterators & Generators	JavaScript	Iterators & Generators	Advanced
21	How does Python's list implementation achieve amortized O(1) append performance despite lists being dynamically resizable arrays under the hood? Python › Data Types & Structures	Python	Data Types & Structures	Advanced
22	How does the configuration binder handle nested objects, arrays, and complex types when binding a JSON section to a C# class? .NET › Configuration & Options	.NET	Configuration & Options	Advanced
23	How does the configuration binder handle nested objects and arrays when binding a JSON section to a strongly-typed C# class? ASP.NET Core › Configuration & Options Pattern	ASP.NET Core	Configuration & Options Pattern	Advanced
24	What is an ArrayBuffer in JavaScript? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Beginner
25	How do you convert a TypedArray to a regular JavaScript array? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Intermediate
26	What is a TypedArray and how does it relate to ArrayBuffer? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Beginner
27	Name a few common TypedArray types and their byte sizes. JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Beginner
28	What's the difference between map() and forEach()? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Beginner
29	How does filter() work? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Beginner
30	What does reduce() do and what are its arguments? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Beginner
31	What are TypeScript's basic primitive types, and how do you annotate a variable with one? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Beginner
32	How do you type an array of a specific element type, and what are the two equivalent syntaxes? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Beginner
33	What is a tuple, and how does it differ from a regular array type? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Beginner
34	How do you declare and initialize a fixed-size array in C#? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Beginner
35	How do you create and work with a multidimensional (rectangular) array versus a jagged array? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Beginner
36	What is Span<T> and what core performance problem does it solve? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Beginner
37	How do you declare, initialize, and access elements of a one-dimensional array in Java? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Beginner
38	How do you declare and initialize an array of objects (reference types) versus an array of primitives, and what is the key difference in their default values? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Beginner
39	How do you add, remove, and access elements within a PHP array? PHP › Arrays in PHP	PHP	Arrays in PHP	Beginner
40	What is a DataView and when would you use it over a TypedArray? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Intermediate
41	What's the difference between slice() and subarray() on a TypedArray? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Intermediate
42	What's the difference between splice() and slice()? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Intermediate
43	How do find() and findIndex() differ from filter()? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Intermediate
44	What does Array.isArray() solve that typeof can't? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Intermediate
45	How do you make a tuple element optional, and how does that affect the tuple's minimum required length? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Intermediate
46	How do labeled tuple elements improve readability and editor tooling compared to unlabeled tuples? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Intermediate
47	How does a rest element work within a tuple type, like `[string, ...number[]]`? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Intermediate
48	How does Memory<T> differ from Span<T>, and when would you use Memory<T> instead? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Intermediate
49	How do you slice an array or string efficiently without allocating a new array/string, using Span<T> or ReadOnlySpan<T>? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Intermediate
50	What restrictions does the C# compiler enforce on Span<T> because it's a 'ref struct'? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Intermediate
51	How does Java handle array bounds checking, and what exception is thrown when accessing an invalid index? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Intermediate
52	How do you correctly iterate a 2D array using both traditional indexed for-loops and the enhanced for-each loop, and when is each approach preferable? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Intermediate
53	How would you flatten a 2D array into a 1D array, and conversely, reshape a 1D array into a 2D array? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Intermediate
54	How do array_map, array_filter, and array_reduce help you transform and process array data without writing manual loops? PHP › Arrays in PHP	PHP	Arrays in PHP	Intermediate
55	What is array destructuring in PHP, and how does the list function or short array syntax simplify extracting values from an array? PHP › Arrays in PHP	PHP	Arrays in PHP	Intermediate
56	How do you share an ArrayBuffer between a Web Worker and the main thread without copying it? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Advanced
57	How does BigInt64Array differ from a standard numeric TypedArray? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Advanced
58	How can you grow an ArrayBuffer after it's been created? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Advanced
59	How do you handle out-of-range writes to a TypedArray safely? JavaScript › ArrayBuffer, TypedArrays & Binary Data	JavaScript	ArrayBuffer, TypedArrays & Binary Data	Advanced
60	How does sort() compare values by default, and how do you fix numeric sorting? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Advanced
61	What is the difference between flat() and flatMap()? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Advanced
62	How do you efficiently remove duplicate values from an array? JavaScript › Arrays & Array Methods	JavaScript	Arrays & Array Methods	Advanced
63	How does TypeScript infer a tuple type versus a regular array type from an array literal, and how do 'as const' assertions change this? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Advanced
64	How would you write a generic type that extracts the length of a tuple type at compile time? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Advanced
65	How do variadic tuple types (using generic rest elements) let you build type-safe function composition or concat utilities? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Advanced
66	How does readonly interact with tuple types, and what does `readonly [number, number]` prevent compared to a mutable tuple? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Advanced
67	How would you use conditional types together with tuples to implement a type-safe 'head' and 'tail' extraction, similar to array destructuring at the type level? TypeScript › Primitive Types, Arrays & Tuples	TypeScript	Primitive Types, Arrays & Tuples	Advanced
68	How does 'stackalloc' work together with Span<T> to allocate memory on the stack instead of the heap? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Advanced
69	How would you write a high-performance CSV field parser using ReadOnlySpan<char> that avoids all intermediate string allocations? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Advanced
70	How does the modern .NET Span-based string.Split (via MemoryExtensions) or manual span-splitting reduce garbage collection pressure compared to string.Split()? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Advanced
71	How would you use Span<T> to implement an in-place array reversal or sorting algorithm without allocating a temporary array? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Advanced
72	How would you implement an efficient in-place algorithm on a 2D array, such as rotating a matrix 90 degrees, while minimizing extra memory allocation? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Advanced
73	How would you implement a custom, resizable dynamic array (similar to ArrayList's internal mechanism) from scratch using a raw Java array, including the amortized doubling growth strategy? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Advanced
74	How would you implement a memory-efficient sparse matrix representation in Java when a large 2D array would mostly contain zero/default values, avoiding the memory waste of a full dense array? Java › Arrays & Multidimensional Arrays	Java	Arrays & Multidimensional Arrays	Advanced
75	What is the role of Span<T> and Memory<T> in .NET, and why can't Span<T> be used inside an async method? C# › Arrays, Span<T> & Memory<T>	C#	Arrays, Span<T> & Memory<T>	Advanced
76	What is console.table() useful for? JavaScript › Debugging, Testing & Tooling	JavaScript	Debugging, Testing & Tooling	Beginner
77	How do you destructure values out of an array? JavaScript › Destructuring, Spread & Rest	JavaScript	Destructuring, Spread & Rest	Beginner
78	What does the spread operator (...) do when used on an array? JavaScript › Destructuring, Spread & Rest	JavaScript	Destructuring, Spread & Rest	Beginner
79	How does a Set differ from an array? JavaScript › Map, Set, WeakMap & WeakSet	JavaScript	Map, Set, WeakMap & WeakSet	Beginner
80	What are some commonly used Math object methods? JavaScript › Numbers, Math & BigInt	JavaScript	Numbers, Math & BigInt	Beginner
81	What is a numeric enum, and what values do its members get by default? TypeScript › Enums	TypeScript	Enums	Beginner
82	What is the difference between List<T> and an array (T[]) in terms of resizing? C# › Collections	C#	Collections	Beginner
83	What are the eight primitive data types in Java, and how do they differ fundamentally from reference types like String or a custom class? Java › Java Fundamentals: Syntax, Data Types & Operators	Java	Java Fundamentals: Syntax, Data Types & Operators	Beginner
84	What are the basic data types available in PHP? PHP › Basics & Types	PHP	Basics & Types	Beginner
85	What is an anonymous function in PHP, and how does it differ from a regular named function? PHP › Closures & Anonymous Functions	PHP	Closures & Anonymous Functions	Beginner
86	How do you convert a PHP array or object into a JSON formatted string using json_encode? PHP › JSON Handling in PHP	PHP	JSON Handling in PHP	Beginner
87	How does SimpleXML let you access nested elements and attributes within an XML document using a natural, object like syntax? PHP › XML Handling in PHP	PHP	XML Handling in PHP	Beginner
88	What is Number.MAX_SAFE_INTEGER and what breaks beyond it? JavaScript › Numbers, Math & BigInt	JavaScript	Numbers, Math & BigInt	Intermediate
89	What is BigInt and how do you create one? JavaScript › Numbers, Math & BigInt	JavaScript	Numbers, Math & BigInt	Intermediate
90	What is parameter property shorthand in a constructor, and what does it expand to? TypeScript › Classes: Access Modifiers, Abstract Classes & Implements	TypeScript	Classes: Access Modifiers, Abstract Classes & Implements	Intermediate
91	What is 'reverse mapping' in numeric enums, and why don't string enums support it? TypeScript › Enums	TypeScript	Enums	Intermediate
92	How do computed and constant enum members work when mixing string and numeric-style initialization? TypeScript › Enums	TypeScript	Enums	Intermediate
93	How do rest parameters work with type annotations, and what type must the annotation be? TypeScript › Function Types, Overloads & Optional/Default Parameters	TypeScript	Function Types, Overloads & Optional/Default Parameters	Intermediate
94	How does 'as const' behave differently when applied to an array literal versus a plain object literal? TypeScript › Readonly, const Assertions & Immutability	TypeScript	Readonly, const Assertions & Immutability	Intermediate
95	What are the key performance differences between ArrayList and LinkedList for common operations (random access, insertion/removal at various positions), and when would you choose one over the other? Java › Collections Framework	Java	Collections Framework	Intermediate
96	What is the global Buffer class, and how does it relate to the process object's broader role in giving access to system-level capabilities? Node.js › Global Objects & the process Object	Node.js	Global Objects & the process Object	Intermediate
97	What are PHP's comparison operators, and how does the spaceship operator introduced in PHP 7 simplify writing custom comparison logic? PHP › Basics & Types	PHP	Basics & Types	Intermediate
98	What are arrow functions introduced in PHP 7.4, and how do they simplify writing short closures compared to traditional anonymous functions? PHP › Closures & Anonymous Functions	PHP	Closures & Anonymous Functions	Intermediate
99	What are default parameter values and variadic functions in PHP, and how do they add flexibility to how a function can be called? PHP › Functions & Scope	PHP	Functions & Scope	Intermediate
100	How does yield from let a generator delegate part of its iteration to another generator or an array, and why is this useful? PHP › Generators & Iterators	PHP	Generators & Iterators	Intermediate
101	How do control structures like loops and conditionals work within Blade and Twig templates, and how do they compare to writing the equivalent raw PHP directly inside an HTML file? PHP › Template Engines (Blade & Twig)	PHP	Template Engines (Blade & Twig)	Intermediate
102	How does the DOM extension provide a more powerful and flexible alternative to SimpleXML when you need to actually modify or construct an XML document rather than only read one? PHP › XML Handling in PHP	PHP	XML Handling in PHP	Intermediate
103	What is XPath, and how does it let you query and extract specific elements from an XML document using a powerful, standardized path based query syntax? PHP › XML Handling in PHP	PHP	XML Handling in PHP	Intermediate
104	How do you sort an array of strings correctly for a given language using Intl.Collator? JavaScript › Date, Time & Internationalization (Intl API)	JavaScript	Date, Time & Internationalization (Intl API)	Advanced
105	How would you group an array of objects by a property using Map, and how does the newer Object.groupBy() compare? JavaScript › Map, Set, WeakMap & WeakSet	JavaScript	Map, Set, WeakMap & WeakSet	Advanced
106	How do you create a type-safe iteration over all values of a string enum? TypeScript › Enums	TypeScript	Enums	Advanced
107	How do template literal types interact with number and bigint literal types embedded inside them? TypeScript › Template Literal Types	TypeScript	Template Literal Types	Advanced
108	How would you use template literal types to enforce a semantic-versioning-style string format at compile time? TypeScript › Template Literal Types	TypeScript	Template Literal Types	Advanced
109	How would you implement a multi-dimensional indexer, like a Matrix class supporting matrix[row, col] syntax? C# › Indexers & Operator Overloading	C#	Indexers & Operator Overloading	Advanced
110	What is the Large Object Heap (LOH), and why do objects allocated there behave differently from regular small objects? C# › Memory & Garbage Collection	C#	Memory & Garbage Collection	Advanced
111	How would you use ArrayPool<T> to reduce garbage collection pressure in a high-throughput, buffer-allocating hot path? C# › Memory & Garbage Collection	C#	Memory & Garbage Collection	Advanced
112	How does Java's integer division and modulo operator behave with negative operands, and how does this differ from the mathematical definition of modulo used in some other contexts (like array indexing wraparound)? Java › Java Fundamentals: Syntax, Data Types & Operators	Java	Java Fundamentals: Syntax, Data Types & Operators	Advanced
113	What is a common pitfall when using async/await inside Array.prototype.forEach(), and how do you fix it? Node.js › Async Patterns	Node.js	Async Patterns	Advanced
114	How does recursion work in PHP functions, and what are the practical considerations, such as stack depth limits, when writing a recursive function? PHP › Functions & Scope	PHP	Functions & Scope	Advanced
115	How do generators help implement memory efficient data processing pipelines, chaining multiple transformation steps together without ever loading an entire dataset into memory at once? PHP › Generators & Iterators	PHP	Generators & Iterators	Advanced
116	How can __clone be used to customize what happens when an object is duplicated using PHP's clone keyword, particularly for handling deep copies of nested objects? PHP › Magic Methods	PHP	Magic Methods	Advanced
117	How can regular string concatenation inside a large loop lead to performance problems, and what alternative approaches help avoid this issue when building up very large strings? PHP › Strings & String Functions	PHP	Strings & String Functions	Advanced