How can I represent a range in Java

Question

Let s say an integer should be within the range   0   2147483647   I want to check whether an integer variable falls within this range  I know it can be accomplished by a simple if-else statement  but is there a more efficient way to check whether it s within the range    I d rather not do this   if  foo  gt   0  amp  amp  foo  lt   2147483647            do something

User · Answer

I know this is quite an old question  but with Java 8 s Streams you can get a range of ints like this      gives an IntStream of integers from 0 through Integer MAX VALUE IntStream rangeClosed 0  Integer MAX VALUE      Then you can do something like this   if  IntStream rangeClosed 0  Integer MAX VALUE  matchAny n - gt  n    A            do something   else          do something else

User · Answer

For a range of Comparable I use the following     public class Range lt T extends Comparable lt T gt  gt                    Include start  end in   link Range              public enum Inclusive  START END BOTH NONE                     link Range  start and end values             private T start  end      private Inclusive inclusive                  Create a range with   link Inclusive START          param start        lt br  gt  Not null safe         param end        lt br  gt  Not null safe             public Range T start  T end     this start  end  null                      param start        lt br  gt  Not null safe         param end        lt br  gt  Not null safe        param inclusive        lt br  gt If null   link Inclusive START  used             public Range T start  T end  Inclusive inclusive             if  start    null      end    null                 throw new NullPointerException  Invalid null start   end value                      setInclusive inclusive            if  isBigger start  end                  this start   end    this end     start           else               this start   start   this end     end                                  Convenience method             public boolean isBigger T t1  T t2    return t1 compareTo t2   gt  0                    Convenience method             public boolean isSmaller T t1  T t2    return t1 compareTo t2   lt  0                    Check if this   link Range  contains t        param t        lt br  gt Not null safe        return       false for any value of t  if this start equals this end             public boolean contains T t    return contains t  inclusive                     Check if this   link Range  contains t        param t        lt br  gt Not null safe        param inclusive        lt br  gt If null   link Range inclusive  used        return       false for any value of t  if this start equals this end             public boolean contains T t  Inclusive inclusive             if t    null                throw new NullPointerException  Invalid null value                       inclusive    inclusive    null    this inclusive   inclusive           switch  inclusive                case NONE                  return   isBigger t  start   amp  amp  isSmaller t  end                 case BOTH                  return     isBigger start  t    amp  amp    isBigger t  end                  case START  default                  return     isBigger start  t    amp  amp   isBigger end  t                  case END                  return   isBigger t  start    amp  amp     isBigger t  end                                      Check if this   link Range  contains other range         return        false for any value of range  if this start equals this end             public boolean contains Range lt T gt  range            return contains range start   amp  amp  contains range end                         Check if this   link Range  intersects with other range         return        false for any value of range  if this start equals this end             public boolean intersects Range lt T gt  range            return contains range start     contains range end                        Get   link  start             public T getStart     return start                   Set   link  start         lt br  gt Not null safe        lt br  gt If start  gt  end they are switched            public Range lt T gt  setStart T start             if start compareTo end  gt 0                this start   end              this end    start           else               this start   start                    return this                       Get   link  end             public T getEnd      return end                    Set   link  end         lt br  gt Not null safe         lt br  gt If start  gt  end they are switched            public  Range lt T gt  setEnd T end             if start compareTo end  gt 0                this end    start              this start   end           else               this end   end                    return this                       Get   link  inclusive             public Inclusive getInclusive     return inclusive                   Set   link  inclusive         param inclusive       lt br  gt If null   link Inclusive START  used            public  Range lt T gt  setInclusive Inclusive inclusive             this inclusive    inclusive    null    Inclusive START   inclusive          return this             This is a somewhat shorted version  The full code is available here

User · Answer

Apache Commons Lang has a Range class for doing arbitrary ranges   Range lt Integer gt  test   Range between 1  3   System out println test contains 2    System out println test contains 4      Guava Range has similar API   If you are just wanting to check if a number fits into a long value or an int value  you could try using it through BigDecimal  There are methods for longValueExact and intValueExact that throw exceptions if the value is too big for those precisions

User · Answer

If you are checking against a lot of intervals  I suggest using an interval tree

User · Answer

You could create a class to represent this  public class Range       private int low      private int high       public Range int low  int high           this low   low          this high   high             public boolean contains int number           return  number  gt   low  amp  amp  number  lt   high             Sample usage   Range range   new Range 0  2147483647    if  range contains foo           do something

User · Answer

You could use java time temporal ValueRange which accepts long and would also work with int   int a   2147     Use java 8 java time temporal ValueRange  The range defined   is inclusive of both min and max  ValueRange range   ValueRange of 0  2147483647    if range isValidValue a         System out println  in range     else       System out println  not in range

User · Answer

import java util Arrays   class Soft      public static void main String   args           int   nums range 9  12           System out println Arrays toString nums              static int   range int low  int high           int   a new int high-low           for int i 0 j low i lt high-low i   j                 a i  j                    return a             My code is similar to Python s range

User · Answer

You will have an if-check no matter how efficient you try to optimize this not-so-intensive computation    You can subtract the upper bound from the number and if it s positive you know you are out of range  You can perhaps perform some boolean bit-shift logic to figure it out and you can even use Fermat s theorem if you want  kidding    But the point is  why  do you need to optimize this comparison  What s the purpose

[java] How can I represent a range in Java?

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