How To Banking Concern Lucifer If String Contains But About Other Substring Inward Java? Contains() Together With Indexof() Example

You tin sack role contains(), indexOf() together with lastIndexOf() method to banking corporation gibe if i String contains roughly other String inward Java or not. If a String contains roughly other String together with then it's known equally a substring. The indexOf() method convey a String together with render starting seat of the string if it exists, otherwise it volition render -1. For instance "fastfood".indexOf("food") volition render four merely "fastfood".indexOf("Pizza") volition render -1. This is the easiest way to examine if i String contains roughly other substring or not. The minute method is lastIndexOf() which is similar to indexOf() merely kickoff the search from the tail, merely it volition besides render -1 if substring non industrial plant life inward the String or the concluding seat of the substring, which could live anything betwixt 0 together with length -1.

The 3rd method you lot tin sack role to banking corporation gibe if i String contains roughly other inward Java is contains() method of String. This method returns truthful if a substring is introduce inward String, or simulated otherwise. The entirely departure betwixt contains() together with indexOf() is that erstwhile render a boolean value spell afterward render an int value. Let's meet roughly examples of contains() together with indexOf() to demonstrate how you lot tin sack role this method to search for a substring inward a String inward java.

Searching Using indexOf

I receive got used indexOf() quite frequently to banking corporation gibe if String contains a detail grapheme or not, merely it tin sack manifestly live used to banking corporation gibe if a String contains roughly other substring or not. Given this method await a String, you lot tin sack top a unmarried grapheme string e.g. "a" or a substring e.g. "abc", technically speaking both are substring. What is to a greater extent than of import is that the indexOf() method render -1 when the string on which indexOf() has been called doesn't comprise the string passed equally declaration i.e. "abcd".indexOf("e") volition render -1

hither is how you lot tin sack role indexOf() to examine if String contains a grapheme or substring inward Java:

String input = "Android gave novel life to Java"; boolean isFound = input.indexOf("Android") !=-1? true: false; //true

Similarly, you lot tin sack banking corporation gibe if String contains a detail grapheme or non e.g.

boolean isExists = "iPhone".indexOf("i");

This volition render 0, which is non -1 which agency "iPhone" contains "i".

One of import matter to banking corporation annotation near indexOf() together with lastIndexOf() method is that both of them perform case-sensitive search, which agency if you lot search "iPhone".indexOf("I") it volition render false. If you lot desire to perform a case-insensitive search together with then you lot must convert both inputs together with search String into the same instance e.g. upper or lower instance together with and then telephone band the indexOf() method, equally shown inward our sample program. Please see Java: Influenza A virus subtype H5N1 Beginner's Guide past times Herbert Schildt to larn to a greater extent than near String related methods inward Java.

Searching using contains()

The contains() method provides the best way to banking corporation gibe if String contains roughly other substring or not. It reads good together with returns boolean, which agency you lot tin sack direct role it within if statements. The contains method returns truthful if together with entirely if this string contains the specified sequence of char values. It besides throws NullPointerException if substring passed to it is null. The entirely number amongst the contains() method is that it was added to Java 1.5, which agency you lot cannot role it on the before version. On the other paw indexOf() method exists from JDK 1.0 thence you lot tin sack it everywhere.

hither is an instance of how to role the contains() method to banking corporation gibe if i string contains roughly other String inward Java:

String examine = "Java8 makes Java to a greater extent than powerful"; boolean isFound = text.contains("Java8"); // true

Similar to indexOf() this method besides performs case-sensitive search thence if you lot input is inward unlike instance together with then this volition render false. If you lot desire to do case-insensitive search together with then role the same technique, convert both input together with search string inward same instance together with and then telephone band the contains() method. If you lot are concerned near surgery of contains(), indexOf(), together with lastIndexOf() method together with then delight see Java Performance The Definitive Guide By Scott Oaks to larn to a greater extent than near surgery testing together with analysis.

Java Program to banking corporation gibe if i String contains another

Here is our sample Java programme to demonstrate how to role the indexOf() together with contains() method to banking corporation gibe if i String contains roughly other substring inward Java or not.

package hello;  public class SubStringProblem {    public static void main(String[] args) {      // 1st instance - You tin sack role the indexOf() method to banking corporation gibe if     // a String contains roughly other substring inward Java     // if it does together with then indexOf() volition render the starting index of     // that substring, otherwise it volition render -1      System.out         .println("Checking if i String contains roughly other String using indexOf() inward Java");     String input = "Java is the best programming language";     boolean isPresent = input.indexOf("Java") != -1 ? true : false;      if (isPresent) {       System.out.println("input string: " + input);       System.out.println("search string: " + "Java");       System.out.println("does String contains substring? " + "YES");     }      // indexOf is case-sensitive thence if you lot top incorrect case, you lot volition acquire wrong     // result     System.out.println("Doing search amongst unlike case");     isPresent = input.indexOf("java") != -1 ? true : false;     System.out.println("isPresent: " + isPresent); // simulated because indeOf() is                                                    // case-sensitive      // 2d instance - You tin sack besides role the contains() method to banking corporation gibe if     // a String contains roughly other String inward Java or not. This method     // returns a boolean, truthful if substring is industrial plant life on String, or false     // otherwise.     // if you lot bespeak boolean role this method rather than indexOf()     System.out         .println("Checking if i String contains roughly other String using contains() inward Java");     input = "C++ is predecessor of Java";     boolean isFound = input.contains("Java");     if (isFound) {       System.out.println("input string: " + input);       System.out.println("search string: " + "Java");       System.out.println("does substring is industrial plant life within String? " + "YES");     }      // contains is besides case-sensitive     System.out.println("Searching amongst unlike case");     isFound = input.contains("java");     System.out.println("isFound: " + isFound); // simulated because indeOf() is                                                // case-sensitive    } }  Output Checking if i String contains roughly other String using indexOf() in Java input string: Java is the best programming language search string: Java does String comprise substring? YES Doing search with unlike case isPresent: false Checking if i String contains roughly other String using contains() in Java input string: C++ is the predecessor of Java search string: Java does substring is industrial plant life within String? YES Searching for unlike case isFound: false

Here is besides a dainty diagram to explicate how indexOf works amongst positions of characters within String:

That's all near how to banking corporation gibe if i String contains roughly other substring inward Java. You tin sack role whatever of the 3 methods, indexOf(), lastIndexOf(), or contains() to verify that. General guideline is that to role indexOf() if you lot bespeak the seat of substring otherwise contains() is to a greater extent than readable together with render a boolean value which tin sack live used inward if weather directly. Let me know if you lot come upward across whatever other way to banking corporation gibe if a String contains a substring or not. Also, if you lot are learning Java from scratch together with then I advise to stick amongst a practiced majority like Java: How to Program past times Dietel to larn fundamentals before jumping around.

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