Common ways to use C # string strings

1---The declaration of the string:

1, String S=new string (char[] arr)//The character array is converted to a string based on the declaration of a character string.

2, String s=new string (char r,int i)//generates the I-character R strings.

2---The usual static method of the string:

1. Comparison of Compare strings (in dictionary order)

int result= String.Compare (string str1,string str2);

When str1 > str2, return 1

　　　When str1 = str2, returns 0

When str1 < STR2, return-1

String.Compare (String str1,string str2,bool ignoreCase)//Ignore case comparison

2, concat connection method parameters are many, commonly used concat (string str1,string str2);

String str=string. Concat ("W", "E"); Str= "we";

3, format parameter processing, equivalent to Console.WriteLine ();

String Str=string.format ("Today {0} is very hot", "weather");//str= "The weather is very hot today";

4, IsNullOrEmpty judge whether the character is null or empty, the return value is bool;

String str1= "Hahha";

BOOL B1=string. IsNullOrEmpty (str);//b1=false;

String Str2= "";

BOOL B2=string. IsNullOrEmpty (str2);//b2=true;

String Str3=null;

BOOL B3=string. IsNullOrEmpty (STR3);//b3=true;

5. Merging of join strings

　　　　string. Join (String str,string[] strarr); //Strarr The contents of the array into a new string and adds a delimiter between each of the corresponding array str

String strs=string. Join (",", string[]{"W", "E", "R", "T"});//strs= "W,e,r,t";

3---"string Common example method:

1. Contains determines whether a character is contained in a string and returns a bool value.

String str= "so Tired";

BOOL B=str. Contains ("tired");//b=true;

2. EndsWith and StartsWith determine if a string has started or ended

String Str= "The rain is so great";

BOOL B1=str. StartsWith ("large");//b1=false;

BOOL B2-str. EndsWith ("Ah");//b2=true;

3, Equals compares two strings for equality

String str1= "ASD";

String str2= "ERT";

BOOL B = str1.  Equals (STR2); B=false;

bool <strname>. Equals (String str, stringcomparison.ordinalignorecase)//indicates case insensitive

4, IndexOf and LastIndexOf determine where the string first appears (INDEXOF) and the last occurrence (LastIndexOf), and if not, the return value is-1

String str = "The rain is very big today, the weather is very cold";

int I=STR. IndexOf ("very"); i=4;

int I=STR. LastIndexOf ("very");//j=8;

int M=STR. IndexOf ("small");//m=-1;

5, replace the replacement string (the character is also possible), return the new string

String str= "so Sleepy";

String S=str. Replace ("Sleepy", "spirit");//s= "good spirit";

6. Insert Inserts

　　　　Inserts a character at the index position of the string, and the original character moves back to a new string

String Str= "late at Night";

String S=str. Insert (1, "already");//s= "The Night is deep."

7. Remove delete string (character)

Removes the string starting from startindex, the length of which is long, and the remaining words conform to a new string (<strName> = <strname>. Remove (startindex,length);)

String Str= "The Night is Deep";

String S=str. Remove (//s=);

8, split the string <strName> in the sep array of characters, split the resulting content into an array (string[] <strname>. Split (params char[] sep);)

String Str= "I, really, very sleepy; yes";

String[] S=str. Split (new char () {', ', ', ', ', '} '),//s=string[]{"I", "true", "Good Sleepy", "yes"};

9. Substring Intercept character <str> start intercept with index, and intercept lenth characters (string <str>. Substring (Index,lenth))

String str= "still raining";

String S=str. Substring (2,2);//s= "Rain";

10, ToCharArray the string into a character array (<STRING>. ToCharArray ())

String Str= "The rain is already small";

Char[] S=str. ToCharArray ();//s=char[]{' rain ', ' already ', ' Jing ', ' small ', ' up '};

11, Trim () go out on both sides of the space

String str= "DD";

String S=str. Trim ();//s= "DD";

12, ToUpper (converted to uppercase) and tolower (converted to lowercase)

String s= "Raser";

String S1=s.toupper ();//s1= "Raser";

String S2=s.tolower ();//s2= "Raser";

　　　　

　　　　

　　　　

Common ways to use C # string strings