Java Basics String

string literal declaration: String string = "12345";

1, the concatenation of strings:

String str1 = "123";

String str2 = "456";

Method One:

System.out.println (str1 + SR2);

Method Two:

System.out. println (Str1.concat (str2));

2. Deletion and interception of strings:

　　String str = "123ASDZXVCAAAA"

　　Method One: Delete all the numbers in the string

System.out.println (Str.replaceall ("\\d", ""));

Method Two: intercept string, delete

1, System.out.println (str.substring (int i)); The string is truncated from subscript I, and the element preceded by I is taken away;

2, System.out.println (str.substring (int i, int j));//The string is truncated from subscript I to subscript j;

3, System.out.println (Str.replaceall ("A", "" ")); Replace all A in the STR string with "";

3, ASCII code conversion:

　　String str = "123ASDASD";

SYSTEM.OUT.PRINTLN (Str.charat (int i)); Gets the ASCII code for the character labeled I,

4. Get the specified subscript element

　　String str = "1234ABCD";

System.　　Out. println ("str.indexof (int i)"); Get the element labeled I;

5. Check if the string contains an element

　　String str = "123qwer";

if (Str.contanins ("123")) {

System.out.println ("contains 123")

}

　　　　

Java Basics String