concatenation

1 the state of being linked together as in a chain; union in a linked series

2 the linking together of a consecutive series of symbols or events or ideas etc; "it was caused by an improbable concatenation of circumstances"

3 a series of things depending on each other as if linked together; "the chain of command"; "a complicated concatenation of circumstances" [syn: chain]

4 the act of linking together as in a series or chain

English

Pronunciation

/kɑn.ˌkæt.ɪ.ˈnæɪ.ʃən/

• Rhymes: -eɪʃǝn

Noun

1. (countable or uncountable) A series of links united; a series or order of things depending on each other, as if linked together; a chain, a succession.
   • 1927, Albert Einstein, as quoted by H. G. Kessler in The Diary of a Cosmopolitan (1971)

     Try and penetrate with our limited means the secrets of nature and you will find that, behind all the discernible concatenations, there remains something subtle, intangible and inexplicable.

See also

• concatenate

In computer programming, concatenation is the operation of joining two character strings end to end. For example, the strings "foo" and "bar" may be concatenated to give "foobar". In programming languages, string concatenation is a binary operation usually accomplished by putting a concatenation operator between two strings (operands).

For example, the following expression uses the "+" symbol as the concatenation operator:

print "Hello " + "World";

which produces the output:

Hello World

Different languages

Different languages use different operators. Most languages use the "+" sign though several deviate from this norm.

Examples

+ ;; ActionScript, BASIC, C++, C#, Java, JavaScript, Pascal, Python, Ruby, Windows PowerShell, SQL & ;; Ada, AppleScript, VHDL, Visual Basic . ;; Perl (before version 6), PHP || ;; REXX, SQL

For a more detailed comparison, please see the concatenation comparison article.

Programming conventions

Assignment

Many languages, such as PHP and JavaScript have a variant of the assignment operator that allows concatenation and assignment to a variable in one statement.

For example, in PHP and Perl:

//Example 1 (concatenation operator ".") $var = "Hello "; $var = $var . "World";

//Example 2 (combined assignment and concatenation ".=") $var = "Hello "; $var .= "World";

Both examples produce the same result.

Interpolation

Some languages, (such as Perl, PHP, and most Unix shells), support variable interpolation as an alternative form of string concatenation.

For example, in Perl, the concatenation syntax:

my $stringVar; $stringVar = "World"; print "Hello " . $stringVar;

can be substituted with the string literal syntax:

my $stringVar; $stringVar = "World"; print "Hello $stringVar";

since double quoted string literals in Perl indicate scalar variables with the sigil ($) character.

See also

• Formal language

External links

• Concatenation of languages (different from concatenation on strings)