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How to Compare a String to Two Other Strings All in the Same Line Using .equals() [duplicate]

This question already has answers here:
Best way to format multiple 'or' conditions in an if statement
(8 answers)
Closed 1 year ago.
Let's say I am trying to assign variable hit to true or false depending on whether user input is equal to either "yes" or "y" (I have the .toLowerCase() handled). Is there a way I can use .equals in a way that compares one string to two other strings all in the same line? I did a bit of searching, but I did not find anything, possibly because of the wording of a question like this.
My line of code:
boolean hit = kb.next().toLowerCase.equals("y"); // Change something to see if kb.next() also equals "yes"
So, to repeat, the code should see whether string a equals string b or string c.
If it is impossible to do this on one line, then just say so in the comments or provide an alternative that is hopefully concise.

You can't use equals to compare with two strings unless you call it twice, like this:
String input = kb.next().toLowerCase();
boolean hit = input.equals("y") || input.equals("yes");
You could alternatively use a regex:
boolean hit = input.matches("y(es)?");
Or if you don't mind matching the string "ye" as well as "y" and "yes", you could use startsWith:
boolean hit = "yes".startsWith(input);

Java - Never Quitting While Loops [duplicate]

This question already has answers here:
How do I compare strings in Java?
(23 answers)
Closed 4 years ago.
I am trying to create a file system/file commander in java, and I want to make the following loop a quit system that triggers when I type dc.
public static void main(String[] args)
boolean x; x=true;
String dc; dc="dc";
while (x=true) {
System.out.println("_____________________");
System.out.println("local disk C:");
System.out.println("bin");
System.out.println("_____________________");
String ltstcmdddd; ltstcmdddd = ltstcm.nextLine();
if (ltstcmdddd==dc) {
break;
}
}
So this is the code for the file commander, it's part of a game so ltstcm is a scanner, and lstcmd is a string you use to input commands for the game (Can't re-use it, I kept adding d's.), like I said before I want to leave this loop when I write dc, I made an if that checked lstcmdddd, I tried with checkingif (lstcmdddd=="dc") and that didn't work. I suspected that changing the value of the boolean x wouldn't work after discovering 'break', that failed. I then tried defining the string dc which contained "dc", and that didn't work either. I searched Stack Overflow about quitting loops, quitting loops failing, and changing values after defining a variable correctly. Nothing relevant to my problem, nothing I could salvage to solve the problem. (I AM NOT ASKING ABOUT COMPARISON!)

You cannot use the == comparison for strings, you have to use .equals, ie: lstcmdddd.equals("dc").
In Java, Strings are objects, so you cannot compare them using the double equal operator. As you are doing that however, your conditional will always return false and the break statement will never execute.

You should rather use .equals than ==. == is used to compare a single char or number, while .equals is used to compare strings.
[...]
String ltstcmdddd; ltstcmdddd = ltstcm.nextLine();
if (ltstcmdddd.equals(dc)) {
[...]

Use ltstcmdddd.equals(dc) instead of ltstcmdddd==dc
The function checks the actual contents of the string, the == operator checks whether the references to the objects are equal

Checking the existence of a certain array [duplicate]

This question already has answers here:
How do I determine whether an array contains a particular value in Java?
(30 answers)
Closed 8 years ago.
What is the best way to check the existence of a certain array name? for example, if i had a array called:
String array1[] = new String[]{"abc", "def", "ghi"};
what is the best way to check if array1 exists or not?
Additionally, is there a way to see if the string "abc" exists inside the array if we don't know which index "abc" is in?
EDIT: I'm planning to have the user input a string and check if the input string matches with any of the string array variable names

To check whether the array exists you could use
if(array != null){
//some code for when the array exists
} else {
//some other code for when the array does not exist.
}
If you want to check, whether an array has more than 0 entries, please edit your question.
For checking if the string "abc" is part of the array, you can use
if(Arrays.asList(array1).contains("abc")){...}
To learn more about arrays, you should read the documentation for arrays:
http://docs.oracle.com/javase/7/docs/api/java/util/Arrays.html

Why does Eclipse allow string comparisons with ==? [duplicate]

This question already has answers here:
How do I compare strings in Java?
(23 answers)
Closed 8 years ago.
I understand and know why you typically have to use == to compare strings in java, but for some reason I am able to do it in Eclipse. My code is
Code:
public class Test{
public static void main(String [] args){
String str1 = "string";
if(str1 == "string"){
System.out.println("wtf");
}
}
}
Why does this print "wtf" yet using javac from command line does not?

Eclipse allows you to compare references because it is a legitimate comparison. Just probably not the one you really want.
Because of String interning it will sometimes appear to work, but you should not rely upon it unless you know the strings you're comparing have been interned. The correct way to compare Strings for equal value is to use .equals.

It allow cause it probably faster to compare two address than comparing 2 string (but use it with caution, you probably never have to compare two String address).
It is sometime usefull to compare Object memories address, and as long as String is an object, eclipse allow you to compare using ==

Check if string array index is equal to string [duplicate]

This question already has answers here:
How do I compare strings in Java?
(23 answers)
Closed 9 years ago.
So I'm trying to check a list of account names to see if the username entered by the operator is in the database or not. At the moment I have:
for(int i = 0; i < rowCount; i ++){
System.out.println("Stored in array:" + accounts[i+1]);
System.out.println("name entered:" + LoginPage.usrname);
if(accounts[i+1] == LoginPage.usrname){
System.out.println("match");
}else{
System.out.println("no match");
}
}
I tried messing around with things like indexOf string and can't get anything to work. I'm sure there's a simple solution, just having trouble finding one. I don't understand why I can't compare a String array index to a String variable, seems like ti should be cake.

This is what you're looking for:
if(acounts[i+1].equals(LoginPage.usrname))
Using the == operator on Strings in Java doesn't do what you think it does. It doesn't compare the contents of the Strings, but rather their addresses in memory. The equals method compares the contents of the Strings.
As a note that may help you remember, this isn't anything particularly special about Strings. Strings are objects, and in Java, using == to compare objects of ANY type will present the same problem. If you want to compare the contents of two objects of a custom class you create, you'll have to write an equals method for that class. Strings work exactly the same.

String are unique reference type that behave like value type.
At Java when trying to compare String's using == operator, Java will try to check if both of the reference are equals, Not the strings.
In order to achieve a value type comparison you will be to use one of the following:
Method 1: str1.equals(str)
Method 2: str1.compareTo(str) == 0