함수 concat() 편집하기

[[category: String]]
;concat
;Concatenate
;operator + & . ~ ||

==Overview==
*Definition: concatenate(string1,string2) returns string. 
*Description: Concatenates (joins) two strings to each other, returning the combined string. Note that some languages like C have mutable strings, so really the second string is being appended to the first string and the mutated string is returned.

==Bash==
[[category: Bash]]
<source lang='bash'>
str1="Hello,"
str2=" World"
output=$str1$str2
echo $output
# Hello, World
</source>

==C#==
[[category: Csharp]]
<source lang="csharp">
"abc" + "def";      // returns "abcdef"
</source>

==Cmd==
[[category: Cmd]]
<source lang='dos'>
set "str1=Hello,"
set "str2= World"
set "output=%str1%%str2%"
echo %output%
REM shows "Hello, World"
</source>

==D==
[[category: D]]
<source lang="d">
"abc" ~ "def";      // returns "abcdef"
</source>

==Excel==
[[category: Excel]]
<source lang="php">
="ab" & "cd" & "ef" // returns "abcdef"
</source>
<source lang="php">
=CONCATENATE("ab", "cd", "ef") // returns "abcdef"
</source>

==Java==
[[category: Java]]
<source lang="java">
"abc" + "def"      // returns "abcdef"
</source>

==Javascript==
[[category: Javascript]]
<source lang="javascript">
"abc" + "def"      // returns "abcdef"
</source>
<source lang='javascript'>
var str1 = "abc";
var str2 = "def";
var output = str1.concat(str2); // abcdef
</source>
<source lang='javascript'>
var str1 = "abc";
var str2 = "def";
var str3 = "ghi";
var output = str1.concat(str2,str3); // abcdefghi
</source>

==Lisp==
[[category: lisp]]
<source lang=lisp>
(concatenate 'string "abc " "def " "ghi")  ; returns "abc def ghi"
</source>

==Objective-C==
[[category: Objective-C]]
<source lang="objc">
NSString* str = [@"abc" stringByAppendingString:@"def"];
NSLog(@"%@", str); // abcdef
</source>
<source lang='objc'>
NSString* str = [NSString stringWithFormat:@"%@%@%@", @"ab", @"cd", @"ef"];
NSLog(@"%@", str); // abcdef
</source>
<source lang='objc'>
+(NSString*)concat:(NSString*) str, ... {
    NSString* arg;
    va_list args;
    va_start(args, str);
    while((arg = va_arg(args, NSString*))) str = [str stringByAppendingString:arg];
    va_end(args);
    return str;
}
// NSString* str = [Util concat:@"ab", @"cd", @"ef", nil]; // abcdef
</source>

==Pascal==
[[category: Pascal]]
<source lang="pascal">
'abc' + 'def';      // returns "abcdef"
</source>

==Perl==
[[category: Perl]]
<source lang="perl">
'abc'.'def';      # returns "abcdef"
</source>
<source lang="perl">
$str1 = 'abc';
$str2 = 'def';
print $str1.$str2; # abcdef
print "$str1$str2"; # abcdef
print "hello $str1 $str2"; # hello abc def
</source>

==PHP==
[[category: PHP]]
<source lang="php">
'abc'.'def';      // returns "abcdef"
</source>
<source lang="php">
$str1 = 'abc';
$str2 = 'def';
echo $str1.$str2; // abcdef
echo "$str1$str2"; // abcdef
echo "hello $str1 $str2"; // hello abc def
</source>

==Python==
[[category: Python]]
<source lang="python">
'abc' + 'def'      # returns "abcdef"
</source>

==Ruby==
[[category: Ruby]]
<source lang="ruby">
'abc' + 'def'      # returns "abcdef"
</source>

==SQL==
[[category: SQL]]
===MySQL===
[[category: MySQL]]
<source lang='sql'>
SELECT CONCAT(col1, col2) FROM mytable;
UPDATE mytable SET col1 = CONCAT('Hello', col1) WHERE 1;
</source>

===Oracle===
[[category: Oracle]]
<source lang='sql'>
SELECT col1 || '' || col2 FROM mytable;
</source>

===MS SQL===
<source lang='sql'>
SELECT col1 + '' + col2 FROM mytable;
</source>

===PostgreSQL===
*[[#Oracle|See Oracle]]

==VB==
[[category: VB]]
<source lang="vb">
"abc" & "def"       '  returns "abcdef"
"abc" + "def"       '  returns "abcdef"
"abc" & Null        '  returns "abc"
"abc" + Null        '  returns Null
</source>

==See also==
*[[implode]]
*[[merge_file]]
*[[str]]