set a boolean value

Question

Hi I'm working with boolean values and I'm a little bit confused. I have a boolean value:

boolean answer;

This can have two values : yes or not.

If I insert from standard input the string "yes" it became true otherwise false. How can i do?

Bit confused, do you want to use boolean, and then depending on input from the user, set it to true or false? Or do you want to have a item that can be set to yes or not? — dann.dev, Dec 12 '11 at 20:27

score 11 · Accepted Answer · edited Dec 12 '11 at 20:30

11

assuming input is your string:

boolean answer = input.equalsIgnoreCase("yes");

edited Dec 12 '11 at 20:30

Jonathon Faust

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answered Dec 12 '11 at 20:27

Colby

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1

You don't need the `? true : false`. – Oliver Charlesworth Dec 12 '11 at 20:27
what mean that symbol ? and : ? – Mazzy Dec 12 '11 at 20:28
Why the ternary? Just do 'answer = input.equalsIgnoresCase("yes")' – Greg Case Dec 12 '11 at 20:28
Ha, yeah - that is true. Thanks for noticing that. – Colby Dec 12 '11 at 20:28
Mazzy, it is the Ternary operation for Java. See: http://en.wikipedia.org/wiki/Ternary_operation#C.2C_C.2B.2B.2C_C.23.2C_Vala.2C_Objective-C.2C_Java.2C_JavaScript.2C_ActionScript – Colby Dec 12 '11 at 20:31

OldCurmudgeon · Answer 2 · 2011-12-14T00:20:11.003

Something like this may be of value:

private static final Set yesSet = new HashSet( Arrays.asList( new String[] {"1", "aam", "ae", "ām", "ano", "âre", "avunu", "awo", "aye", "ayo", "baht", "bai",
  "bale", "bele", "beli", "ben", "cha", "chaï", "da", "dai", "doy", "e", "é", "éé", "eh", "èh", "ehe", "eja", "eny", "ere", "euh", "evet", "éwa", "giai",
  "ha", "haan", "hai", "hoon", "iè", "igen", "iva", "já", "jā", "ja", "jah", "jes", "jo", "ken", "kha", "khrap", "kyllä", "leo", "naam", "ndiyo", "o", "òc",
  "on", "oo", "opo", "oui", "ova", "ovu", "oyi", "po", "sci", "se", "shi", "si", "sim", "taip", "tak", "tiao", "true", "v", "waaw", "wè", "wi", "ya", "yan",
  "ydw", "yea", "yebo", "yego", "yes", "yo", "yoh", "za", "За", "Так", "Тийм", "نعم", "ใช่", "ค่ะ", "ครับ",
} ) );
public static final boolean stringToBool ( String s ) {
  return ( yesSet.contains( s.toLowerCase() ) );
}

Derived from FreeLang

I believe because some of those characters are not valid UTF-8, the standard for storing java files. — Richard J. Ross III, Dec 13 '11 at 19:59

score 1 · Answer 3 · answered Dec 12 '11 at 20:27

1

You need to perform a string comparison. Use String.equals:

String a = "foo";
String b = "bar";
boolean c = a.equals(b);

answered Dec 12 '11 at 20:27

Oliver Charlesworth

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this is the most elegant way to do it, perhaps using `equalsIgnoreCase` instead. – Sheriff Dec 12 '11 at 20:30

score 0 · Answer 4 · edited Dec 12 '11 at 21:05

0

If your string is saved into response (string response):

if(response.equals("yes")){
 answer = true;
}else{
 answer = false;
}

edited Dec 12 '11 at 21:05

Daniel Fischer

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answered Dec 12 '11 at 20:29

Travis J

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You don't need the conditional, just assign straight to `answer`. – Oliver Charlesworth Dec 12 '11 at 20:29

litterbugkid · Answer 5 · 2011-12-12T20:38:52.043

0

boolean answer;
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String input = "";
try{
   input = br.readLine();
}
catch(IOException e){}

if (input.compareTo("yes") == 0)
{ 
   answer= True;
}
else{
   answer = False;
}

edited Dec 12 '11 at 20:38

answered Dec 12 '11 at 20:30

litterbugkid

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Why is everybody setting the value of a `boolean` by performing an `if` conditional on a `boolean`? – Oliver Charlesworth Dec 12 '11 at 20:32
@OliCharlesworth I'm not performing the `if` on the `boolean`, I'm performing the `if` on the user input – litterbugkid Dec 12 '11 at 20:33
1

Yes you are. `input.compareTo("yes") == 0` is a `boolean`. – Oliver Charlesworth Dec 12 '11 at 20:35
@OliCharlesworth I am comparing `input` with the String `"yes"`, if they are equal `compareTo` will return 0. – litterbugkid Dec 12 '11 at 20:37
1

You can just do `answer = (input.compareTo("yes") == 0);`. Or even better, just use `equals`. – Oliver Charlesworth Dec 12 '11 at 20:40
@Neeta I think Oli means you're wasting time. You could accomplish the same thing with `answer=input.equalsIgnoreCase("yes");` and save space. It may not always be as readable to others though. – Sheriff Dec 12 '11 at 20:40
@Sheriff Ah yes, that is true. I write code as I understand it, and which goes along with the way I think (step by step). I agree that way would save space/would be cleaner. – litterbugkid Dec 12 '11 at 20:42

score 0 · Answer 6 · answered Dec 12 '11 at 20:31

0

This should do it:

boolean answer;
String input = "yes"
if (input.equals("yes")) {
   answer = true;
}

answered Dec 12 '11 at 20:31

Jeff Olson

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Why is everybody setting the value of a `boolean` by performing an `if` conditional on a `boolean`? – Oliver Charlesworth Dec 12 '11 at 20:32
Good point, although sometimes readability is important, too. And it's also possible you'd want to do other things if the input was "yes", as well, meaning an 'if' block would be more appropriate. – Jeff Olson Dec 12 '11 at 20:56

score 0 · Answer 7 · answered Dec 13 '11 at 00:48

0

boolean answer = new Scanner(System.in).nextLine().equalsIgnoreCase("yes");

answered Dec 13 '11 at 00:48

Eng.Fouad

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set a boolean value

7 Answers7