# expression

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## expression

1. communication of emotion through music, painting, etc.
2. Maths a variable, function, or some combination of constants, variables, or functions
3. Genetics the effect of a particular gene on the phenotype
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

## expression

[ik′spresh·ən]
(chemical engineering)
Separation of liquid from a two-phase solid-liquid system by compression under conditions that permit liquid to escape while the solid is retained between the compressing surfaces. Also known as mechanical expression.
(computer science)
A mathematical or logical statement written in a source language, consisting of a collection of operands connected by operations in a logical manner.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

## expression

(programming)
Any piece of program code in a high-level language which, when (if) its execution terminates, returns a value. In most programming languages, expressions consist of constants, variables, operators, functions, and parentheses. The operators and functions may be built-in or user defined. Languages differ on how expressions of different types may be combined - with some combination of explicit casts and implicit coercions.

The syntax of expressions generally follows conventional mathematical notation, though some languages such as Lisp or Forth have their own idiosyncratic syntax.

## expression

(1) See Expression Studio.

(2) In programming, a line of source code that returns a value when executed. An expression can comprise any combination of variables, values, operators and functions. For example, a=b+c and price=2*cost are expressions. The more complicated expression (strlen(text_string)*2) is a C example that uses a string length function and returns a value that is twice the number of characters in the string of text. See regular expression.
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References in periodicals archive ?
We generated a cDNA expression library from infarcted mouse hearts using the CloneMiner cDNA library construction kit (Invitrogen).
Scientists at the ARC Centre of Excellence for Coral Reef Studies, James Cook University and the University of Queensland are compiling the world's first detailed gene expression library for Symbiodinium.
Expression library immunisation and RNAi: Expression library immunisation (ELI) in combination with sequence analysis of expressed sequence tags (ESTs), provides an efficient global approach for identification of vaccine antigens that is based on rapid screening of the expressed genes.

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