Chapter13:StringConcatenate

Section13.1:+Operator

strings1=”string1″;

strings2=”string2″;

strings3=s1+s2;//”string1string2″

Section 13.2: Concatenate strings using System.Text.StringBuilder

Concatenating strings using a StringBuildercan offer performance advantages over simple string concatenation using+.Thisisduetothewaymemoryisallocated.Stringsarereallocatedwitheachconcatenation,StringBuilders allocate memory in blocks only reallocating when the current block is exhausted. This can make a huge difference when doing a lot of small concatenations.

StringBuildersb=newStringBuilder();

for(inti=1;i<=5;i++)

{

sb.Append(i);

sb.Append(“”);

}

Console.WriteLine(sb.ToString());//”12345″

CallstoAppend()canbedaisychained,becauseitreturnsareferencetotheStringBuilder:

StringBuildersb=newStringBuilder();

sb.Append(“somestring”)

.Append(“anotherstring”);

Section13.3:ConcatstringarrayelementsusingString.Join

TheString.Joinmethodcanbeusedtoconcatenatemultipleelementsfromastringarray.

string[]value={“apple”,”orange”,”grape”,”pear”};

stringseparator=”,”;

stringresult=String.Join(separator,value,1,2);

Console.WriteLine(result);

Producesthefollowingoutput:”orange,grape”

ThisexampleusestheString.Join(String,String[],Int32,Int32)overload,whichspecifiesthestartindex and count on top of the separator and value.

IfyoudonotwishtousethestartIndexandcountoverloads,youcanjoinallstringgiven.Like this:

string[]value={“apple”,”orange”,”grape”,”pear”};

stringseparator=”,”;

stringresult=String.Join(separator,value); Console.WriteLine(result);

whichwillproduce;

apple,orange,grape,pear

Section13.4:Concatenationoftwostringsusing$

$providesaneasyandaconcisemethodtoconcatenatemultiple strings.

varstr1=”text1″;

varstr2=””;

varstr3=”text3″;

stringresult2=$”{str1}{str2}{str3}”;//”text1text3″