String Methods
1. int length(): Returns the number of characters in the String.
"GeeksforGeeks".length(); // returns 13
2. Char charAt(int i): Returns the character at ith index.
"GeeksforGeeks".charAt(3); // returns ‘k’
3. String substring (int i): Return the substring from the ith index character to end.
"GeeksforGeeks".substring(3); // returns “ksforGeeks”
4. String substring (int i, int j): Returns the substring from i to j-1 index.
"GeeksforGeeks".substring(2, 5); // returns “eks”
5. String concat( String str): Concatenates specified string to the end of this string. (문자열 연결)
String s1 = ”Geeks”;
String s2 = ”forGeeks”;
String output = s1.concat(s2); // returns “GeeksforGeeks”
6. int indexOf (String s): Returns the index within the string of the first occurrence of the specified string.
String s = ”Learn Share Learn”;
int output = s.indexOf(“Share”); // returns 6
7. int indexOf (String s, int i): Returns the index within the string of the first occurrence of the specified string, starting at the specified index.
String s = ”Learn Share Learn”;
int output = s.indexOf("ea",3);// returns 13
8. Int lastIndexOf( String s): Returns the index within the string of the last occurrence of the specified string.
String s = ”Learn Share Learn”;
int output = s.lastIndexOf("a"); // returns 14
9. boolean equals( Object otherObj): Compares this string to the specified object.
Boolean out = “Geeks”.equals(“Geeks”); // returns true
Boolean out = “Geeks”.equals(“geeks”); // returns false
10. boolean equalsIgnoreCase (String anotherString): Compares string to another string, ignoring case considerations.
Boolean out= “Geeks”.equalsIgnoreCase(“Geeks”); // returns true
Boolean out = “Geeks”.equalsIgnoreCase(“geeks”); // returns true
11. int compareTo( String anotherString): Compares two string lexicographically.
int out = s1.compareTo(s2); // where s1 and s2 are
// strings to be compared
This returns difference s1-s2. If :
out < 0 // s1 comes before s2
out = 0 // s1 and s2 are equal.
out > 0 // s1 comes after s2.
11. int compareToIgnoreCase( String anotherString): Compares two string lexicographically, ignoring case considerations.
int out = s1.compareToIgnoreCase(s2);
// where s1 and s2 are
// strings to be compared
This returns difference s1-s2. If :
out < 0 // s1 comes before s2
out = 0 // s1 and s2 are equal.
out > 0 // s1 comes after s2.
Note- In this case, it will not consider case of a letter (it will ignore whether it is uppercase or lowercase).
12. String toLowerCase(): Converts all the characters in the String to lower case.
String word1 = “HeLLo”;
String word3 = word1.toLowerCase(); // returns “hello"
13. String toUpperCase(): Converts all the characters in the String to upper case.
String word1 = “HeLLo”;
String word2 = word1.toUpperCase(); // returns “HELLO”
14. String trim(): Returns the copy of the String, by removing whitespaces at both ends. It does not affect whitespaces in the middle.
String word1 = “ Learn Share Learn “;
String word2 = word1.trim(); // returns “Learn Share Learn”
15. String replace (char oldChar, char newChar): Returns new string by replacing all occurrences of oldChar with newChar.
String s1 = “feeksforfeeks“;
String s2 = “feeksforfeeks”.replace(‘f’ ,’g’); // returns “geeksgorgeeks”
출처 : https://www.geeksforgeeks.org/string-class-in-java/?ref=gcse
String class in Java - GeeksforGeeks
A Computer Science portal for geeks. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions.
www.geeksforgeeks.org
'Coding > Java' 카테고리의 다른 글
| [15] JAVA 생성자 (Constructor) (0) | 2022.11.24 |
|---|---|
| [14] JAVA Math 클래스 메소드 (0) | 2022.11.23 |
| [12] JAVA 예외처리 (0) | 2022.11.23 |
| [11] JAVA String, StringBuilder 클래스 (0) | 2022.11.22 |
| [10] JAVA - 필드(Field) (0) | 2022.11.22 |
