Java Strings

Creating Strings

Java
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String str1 = "This is string 1!";

String str2 = new String("This is string 2");

String str3 = String.valueOf(1234);

Concatenation

Java
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String str1 = 1 + "one" + 1;  // 1one1

String str2 = 2 + 2 + "two";  // 4two

String str3 = "3" + 3 + "three";  // 33three

String str4 = "4" + str1;  // 41one1

String str5 = "5" + String.valueOf(5);  // 55

String str6 = str2.concat(str3); // 4two33three

String Information

Java
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String str = "Welcome";

str.length(); // 7

str.indexOf("e"); // 1

str.indexOf("r"); // -1

str.charAt(2); // l

str.substring(1,3); // el

str.contains("c"); // true

str.startsWith("W"); // true

str.endsWith("e"); // true

str.isBlank(); // false

str.isEmpty(); // false

str.lastIndexOf("e"); // 6

Comparison

Java
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String str1 = "Welcome";

String str2 = new String("Welcome");

String str3 = "welcome";

System.out.println(str1 == str2); // false

System.out.println(str1.equals(str2)); // true

System.out.println(str1.equals(str3)); //false

System.out.println(str1.equalsIgnoreCase(str3)); //true

System.out.println(str1.contains(str2)); // true

System.out.println(str1.contains(str3)); // false

System.out.println(str1.compareTo(str2)); // 0

System.out.println(str1.contentEquals(str2)); // true

System.out.println(str1.contentEquals(str3)); // false

Manipulation

Java
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String str1 = "Welcome";

String str2 = " Welcome ";

System.out.println(str1.toLowerCase()); // welcome

System.out.println(str1.toUpperCase()); // WELCOME

char[] char1 = str1.toCharArray(); // ['W','e','l','c','o','m','e']

System.out.println(char1); // Welcome

String strArr[] = str1.split(""); // ["W","e","l","c","o","m","e"]

System.out.println(String.join(",", strArr)); // W,e,l,c,o,m,e

System.out.println(str2.trim()); // [Welcome]

System.out.println(str2.stripLeading()); // [Welcome ]

System.out.println(str2.stripTrailing()); // [ Welcome]