science

Name–value pair

Name–value pair is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Name–value pair rather than just read about it. In short: A name–value pair, also known as an attribute–value pair, key–value pair, or field–value pair, is a fundamental data representation in computer systems and applications. Designers often desire an open-ended data structure that allows for future extension without modifying existing code or data.

Key takeaways

Name–value pair belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Name–value pair to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Name–value pair from memory before moving on to harder problems.

Reference excerpt

A name–value pair, also known as an attribute–value pair, key–value pair, or field–value pair, is a fundamental data representation in computer systems and applications. Designers often desire an open-ended data structure that allows for future extension without modifying existing code or data. In such situations, all or part of the data model may be expressed as a collection of 2-tuples in the form <attribute name, value> with each element being an attribute–value pair. Depending on the particular application and the implementation chosen by programmers, attribute names may or may not be unique. Common examples include JSON objects such as database records where a column maps to a stored value (e.g., username → johndoe), HTTP headers like Content-Type: text/html, and configuration files with settings expressed as settingType=1.

Examples of use Some of the applications where information is represented as name-value pairs are:

E-mail, in RFC 2822 headers Query strings, in URLs Optional elements in network protocols, such as IP, where they often appear as TLV (type–length–value) triples Bibliographic information, as in BibTeX and Dublin Core metadata Element attributes in SGML, HTML and XML Key–value databases OpenStreetMap map data Windows registry entries Environment variables

Use in computer languages Some computer languages implement name–value pairs, or more frequently collections of attribute–value pairs, as standard language features. Most of these implement the general model of an associative array: an unordered list of unique attributes with associated values. As a result, they are not fully general; they cannot be used, for example, to implement electronic mail headers (which are ordered and non-unique). In some applications, a name–value pair has a value that contains a nested collection of attribute–value pairs. Some data serialization formats such as JSON support arbitrarily deep nesting. Other data representations are restricted to one level of nesting, such as INI file's section/name/value.

See also Attribute (computing) Entity–attribute–value model Query string Key–value database

References

Illustrations

Worked examples

Example 1 — a first encounter with Name–value pair

Start with the simplest possible case. Write down what Name–value pair claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Name–value pair before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Name–value pair ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Name–value pair

In research: Name–value pair appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Name–value pair in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Name–value pair is common in secondary-school and first-year university syllabi. It links to neighbouring topics Data modeling, so understanding it makes those chapters shorter.
In everyday life: Look for Name–value pair outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Name–value pair” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Name–value pair in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Name–value pair means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Name–value pair out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Name–value pair in simple terms?

Why does Name–value pair matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Name–value pair?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Name–value pair.