1/22/2024 0 Comments Java string classWhen a String has no index within another String, it returns a value of -1. No such index exists! So what happens when we run the program? Here we are looking for the index of the String "banana" inside of the String "Hello world!". Hooray! Our program matches with what we expect!īut what if we look for the index of a String that does not exist? public class IndexOfExample3 extends ConsoleProgram Does our program agree? After running the program, it prints The index is 6. From out chart above, we see that this String begins at index 6. Here we are finding the index of the String "World". When we run our program, it prints out The index is 0 as we expect.Ĭonsider another example: public class IndexOfExample2 extends ConsoleProgram You will notice that "Hello" begins at index 0. The top row gives us the index of each character on the corresponding bottom row. Remember, a character's particular position in a string is formally known as its index. Let's take a quick look back at our chart above: 0 For example, here we are finding the index of the String "Hello" within the String "Hello World!": public class IndexOfExample extends ConsoleProgram The indexOf() method tells us the starting position, or the index, of a String within another String. For example, the three Strings "Hello world", "Hello World", and "HELLO WORLD" are all equal when we ignore case. Essentially, this means that we ignore differences in capitalization. equalsIgnoreCase() method does the same thing, but it ignores differences in case between the two strings. equals() method in the previous Strings chapter. You have already learned about using the. The equals Method versus the equalsIgnoreCase Method The right-most column gives an example of using the method. The middle column also tells us what the method does. The method signature includes the name of the method and its parameters. The middle column in the table shows us the method signature. The left-most column in the table shows us the return type of the method. In this section, we will be focusing on some of the key methods from that page which are listed in the table below: If you go to the String documentation page, you will notice that there are a lot of different methods we can use on Strings. This is often easier than navigating through the full Java Documentation website.For example, here is a Google search for the Java String Documentation.When searching for a specific method or class, search using the keywords "Java ". Tip: you can find a specific page in the documentation using a search engine like Google.In this chapter, we will be focusing specifically on the documentation for Strings ( located on this page).The full Java documentation for all methods and classes is located here.The Java Documentation is the reference for how to use different methods and classes.string1 = string2 is NOT the correct way to compare two Strings. string1.equals(string2) is the correct way to compare two Strings.Using = to compare two Strings will result in buggy programs. equals() method to determine if two Strings are exactly the same. Since Strings are objects, we must use the.A String starts with a capital letter whereas primitive types are all lowercase.Strings are not primitive types (like char, int, boolean, double, etc.).Let's review some key points about Strings: You will note that the space between the two words, ' ', is also a character and is located at position 5.Ī character's particular position in a string is formally known as its index. The last character, 'd', is at position 10. The second character, 'e', is at position 1. For example, the first character, 'H', is at position 0. Here is a way to think about this String as a sequence of individual characters: 0Įach character in this string has a position from 0 to 10. Let's look at this example String below: String str = "Hello World" You will remember that Strings are a sequence of characters.
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