Table (information)

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For other uses, see table (disambiguation).

An example table rendered in a web browser using HTML.

A table is both a mode of visual communication and a means of arranging data. The use of tables is pervasive throughout all communication, research and data analysis. Tables appear in print media, handwritten notes, computer software, architectural ornamentation, traffic signs and many other places. The precise conventions and terminology for describing tables varies depending on the context. Moreover, tables differ significantly in variety, structure, flexibility, notation, representation and use.

1 Basic description
- 1.1 Simple table
- 1.2 Multi-dimensional table
2 Generic representation
3 Specific uses
4 Historical relationship to furniture
5 References
6 See also

[edit] Basic description

A table consists of an ordered arrangement of rows and columns. This is a simplified description of the most basic kind of table. Certain considerations follow from this simplified description:

the term row has several common synonyms (e.g., record, k-tuple, vector);
the term column has several common synonyms (e.g., field, parameter, property, attribute);
a column is usually identified by a name;
a column name can consist of a word, phrase or a numerical index;

The elements of a table may be grouped, segmented, or arranged in many different ways, and even nested recursively. Additionally, a table may include metadata, annotations, header^[1], footer or other ancillary features.

[edit] Simple table

The following illustrates a simple table with three columns and six rows. The first row is not counted, because it is only used to display the column names. This is traditionally called a "header row".

Age table:

first	last	age
Nancy	Davolio	33
Nancy	Klondike	43
Nancy	Obesanjo	23
Justin	Saunders	37
Justin	Timberland	26
Justin	Daviolio	16

[edit] Multi-dimensional table

The concept of dimension is also a part of basic terminology. Any "simple" table can be represented as a "multi-dimensional" table by normalizing the data values into ordered hierarchies. A common example of such a table is a multiplication table.

Multiplication table:

*	1	2	3
1	1	2	3
2	2	4	6
3	3	6	9

To illustrate how a simple table can be transformed into a multi-dimensional table, consider the following transformation of the Age table.

Concatenation table:

+	1	2	3
Nancy	Nancy Davolio	Nancy Klondike	Nancy Obesanjo
Justin	Justin Saunders	Justin Timberland	Justin Daviolio

This is structurally identical to the multiplication table, except it uses concatenation instead of multiplication as the operator; and first name and last name instead of integers as the operands.

[edit] Generic representation

As a communication tool, a table allows a form of generalization of information from an unlimited number of different social or scientific contexts. It provides a familiar way to convey information that might otherwise not be obvious or readily understood.

For example, in the following diagram, two alternate representations of the same information are presented side by side. On the left is the NFPA 704 standard "fire diamond" with example values indicated. On the right is a simple table depicting the same values, along with additional information. Both representations convey essentially the same information, but the tabular representation is arguably more comprehensible to someone who is not familiar with the NFPA 704 standard. The tabular representation may not, however, be ideal for every circumstance (for example because of space limitations, or safety reasons).

Fire diamond:

Standard representation

Tabular representation

Risk levels of hazardous materials in this facility:
Health Risk	Flammability	Reactivity	Special
Level 3	Level 2	Level 1

[edit] Specific uses

There are several specific situations in which tables are routinely used as a matter of custom or formal convention.

[edit] Publishing

Cross-reference (Table of contents)

[edit] Mathematics

Arithmetic Multiplication table
Logic Truth table

[edit] Natural sciences

Chemistry (Periodic table)
Oceanography (tide table)

[edit] Information technology

[edit] Computer programming

Data tables are used extensively in computers in many diverse forms, each form representing a distinct data structure or format. Tables are used to control software and minimize load on hardware, by memoizing^[2] results that would otherwise require direct computation.

Examples include:

n-dimensional array;
symbol table;
inode table;
hash table;
file formats such as Comma-separated values

[edit] Software applications

Modern software applications give users the ability to generate, format, and edit tables and tabular data for a wide variety of uses.

Such applications include:

word processing applications;
spreadsheet applications;
presentation software;
tables specified in HTML or another markup language;

[edit] Historical relationship to furniture

In medieval counting houses, the tables were covered with a piece of chequered cloth, to count money. Exchequer is an archaic term for the English institution which accounted for money owed to the monarch. Thus the checkerboard tables of stacks of coins are a concrete realization of this information.