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Filtering arrays for neighbors

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0

Is there an easy way to filter an array of elements quickly to only output the neighbors?

Say I have an array of elements. Now I want to find the neighbors of a specific element.

The code I made works but looks quite ugly and I'd like to find an easier-to-read solution.

My code:

int[] myArray = 6, 8, 9, 12, 30;
// index of element where I want to find the neighbors of
int index = 1;

if(index == 0)
 //first element so only add the right neighbor
 System.out.println(myArray[1]);
 else if(index == myArray.length -1)
 //last element so only add left neighbor
 System.out.println(myArray[index-1]);
 else
 //middle element so add both neighbors
 System.out.println(myArray[index-1]);
 System.out.println(myArray[index+1]);

java arrays nearest-neighbor

share|improve this question

asked Mar 8 at 16:31

solutionM4stersolutionM4ster

135

add a comment | 

0

Is there an easy way to filter an array of elements quickly to only output the neighbors?

Say I have an array of elements. Now I want to find the neighbors of a specific element.

The code I made works but looks quite ugly and I'd like to find an easier-to-read solution.

My code:

int[] myArray = 6, 8, 9, 12, 30;
// index of element where I want to find the neighbors of
int index = 1;

if(index == 0)
 //first element so only add the right neighbor
 System.out.println(myArray[1]);
 else if(index == myArray.length -1)
 //last element so only add left neighbor
 System.out.println(myArray[index-1]);
 else
 //middle element so add both neighbors
 System.out.println(myArray[index-1]);
 System.out.println(myArray[index+1]);

java arrays nearest-neighbor

share|improve this question

asked Mar 8 at 16:31

solutionM4stersolutionM4ster

135

add a comment | 

Is there an easy way to filter an array of elements quickly to only output the neighbors?

Say I have an array of elements. Now I want to find the neighbors of a specific element.

The code I made works but looks quite ugly and I'd like to find an easier-to-read solution.

My code:

int[] myArray = 6, 8, 9, 12, 30;
// index of element where I want to find the neighbors of
int index = 1;

if(index == 0)
 //first element so only add the right neighbor
 System.out.println(myArray[1]);
 else if(index == myArray.length -1)
 //last element so only add left neighbor
 System.out.println(myArray[index-1]);
 else
 //middle element so add both neighbors
 System.out.println(myArray[index-1]);
 System.out.println(myArray[index+1]);

java arrays nearest-neighbor

share|improve this question

asked Mar 8 at 16:31

solutionM4stersolutionM4ster

135

int[] myArray = 6, 8, 9, 12, 30;
// index of element where I want to find the neighbors of
int index = 1;

if(index == 0)
 //first element so only add the right neighbor
 System.out.println(myArray[1]);
 else if(index == myArray.length -1)
 //last element so only add left neighbor
 System.out.println(myArray[index-1]);
 else
 //middle element so add both neighbors
 System.out.println(myArray[index-1]);
 System.out.println(myArray[index+1]);

share|improve this question

asked Mar 8 at 16:31

solutionM4stersolutionM4ster

135

share|improve this question

asked Mar 8 at 16:31

solutionM4stersolutionM4ster

135

asked Mar 8 at 16:31

solutionM4stersolutionM4ster

135

asked Mar 8 at 16:31

solutionM4stersolutionM4ster

135

2 Answers
2

active

oldest

votes

2

Here is a good and short solution:

if(index > 0) System.out.println(myArray[index-1])
if(index < array.length-1) System.out.println(myArray[index+1])

share|improve this answer

edited Mar 8 at 16:48

answered Mar 8 at 16:37

Anton SorokinAnton Sorokin

215314

add a comment | 

0

Actually, using Java 8 you can use this by quite simple lambda solution:

final int[] numbs = 1, 3, 5, 7 ;
int index = 2;
IntStream.rangeClosed(index - 1, index + 1)
 .filter(idx -> idx != index && idx >= 0 && idx < numbs.length)
 .forEach(idx -> System.out.println(numbs[idx]));

But please, create a method that receives your array and index in order to reuse the code.

share|improve this answer

edited Mar 8 at 17:40

answered Mar 8 at 16:42

Rhuan KarlusRhuan Karlus

7151024

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I do not think that this is a good idea, because the streams usually perform for a long time. Also, lambdas are usually more difficult to understand than simple if-else.
  
  – Anton Sorokin
  Mar 8 at 16:47
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  no need to stream the entire range of the array. you can stream just the neighbors IntStream.rangeClosed(index-1, index+1) and filter idx != index && idx >= 0 && idx < numbs.length
  
  – Sharon Ben Asher
  Mar 8 at 16:49
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  And yes, lambdas are hard to understand for people who doesn't study them. So don't use if you don't know how to use them @AntonSorokin and do never use the new Java features too.
  
  – Rhuan Karlus
  Mar 8 at 17:42
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @RhuanKarlus My message doesnt mean that I dont know lambda or I propose not to learn/use new language features. I meant that it is not necessary to use a complicated version when there is a simpler construction.
  
  – Anton Sorokin
  Mar 9 at 5:16
  

  
  
  
  

add a comment | 

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2

Here is a good and short solution:

if(index > 0) System.out.println(myArray[index-1])
if(index < array.length-1) System.out.println(myArray[index+1])

share|improve this answer

edited Mar 8 at 16:48

answered Mar 8 at 16:37

Anton SorokinAnton Sorokin

215314

add a comment | 

2

Here is a good and short solution:

if(index > 0) System.out.println(myArray[index-1])
if(index < array.length-1) System.out.println(myArray[index+1])

share|improve this answer

edited Mar 8 at 16:48

answered Mar 8 at 16:37

Anton SorokinAnton Sorokin

215314

add a comment | 

Here is a good and short solution:

if(index > 0) System.out.println(myArray[index-1])
if(index < array.length-1) System.out.println(myArray[index+1])

share|improve this answer

edited Mar 8 at 16:48

answered Mar 8 at 16:37

Anton SorokinAnton Sorokin

215314

if(index > 0) System.out.println(myArray[index-1])
if(index < array.length-1) System.out.println(myArray[index+1])

share|improve this answer

edited Mar 8 at 16:48

answered Mar 8 at 16:37

Anton SorokinAnton Sorokin

215314

answered Mar 8 at 16:37

Anton SorokinAnton Sorokin

215314

answered Mar 8 at 16:37

Anton SorokinAnton Sorokin

215314

0

Actually, using Java 8 you can use this by quite simple lambda solution:

final int[] numbs = 1, 3, 5, 7 ;
int index = 2;
IntStream.rangeClosed(index - 1, index + 1)
 .filter(idx -> idx != index && idx >= 0 && idx < numbs.length)
 .forEach(idx -> System.out.println(numbs[idx]));

But please, create a method that receives your array and index in order to reuse the code.

share|improve this answer

edited Mar 8 at 17:40

answered Mar 8 at 16:42

Rhuan KarlusRhuan Karlus

7151024

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I do not think that this is a good idea, because the streams usually perform for a long time. Also, lambdas are usually more difficult to understand than simple if-else.
  
  – Anton Sorokin
  Mar 8 at 16:47
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  no need to stream the entire range of the array. you can stream just the neighbors IntStream.rangeClosed(index-1, index+1) and filter idx != index && idx >= 0 && idx < numbs.length
  
  – Sharon Ben Asher
  Mar 8 at 16:49
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  And yes, lambdas are hard to understand for people who doesn't study them. So don't use if you don't know how to use them @AntonSorokin and do never use the new Java features too.
  
  – Rhuan Karlus
  Mar 8 at 17:42
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @RhuanKarlus My message doesnt mean that I dont know lambda or I propose not to learn/use new language features. I meant that it is not necessary to use a complicated version when there is a simpler construction.
  
  – Anton Sorokin
  Mar 9 at 5:16
  

  
  
  
  

add a comment | 

0

Actually, using Java 8 you can use this by quite simple lambda solution:

final int[] numbs = 1, 3, 5, 7 ;
int index = 2;
IntStream.rangeClosed(index - 1, index + 1)
 .filter(idx -> idx != index && idx >= 0 && idx < numbs.length)
 .forEach(idx -> System.out.println(numbs[idx]));

But please, create a method that receives your array and index in order to reuse the code.

share|improve this answer

edited Mar 8 at 17:40

answered Mar 8 at 16:42

Rhuan KarlusRhuan Karlus

7151024

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I do not think that this is a good idea, because the streams usually perform for a long time. Also, lambdas are usually more difficult to understand than simple if-else.
  
  – Anton Sorokin
  Mar 8 at 16:47
  
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  no need to stream the entire range of the array. you can stream just the neighbors IntStream.rangeClosed(index-1, index+1) and filter idx != index && idx >= 0 && idx < numbs.length
  
  – Sharon Ben Asher
  Mar 8 at 16:49
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  And yes, lambdas are hard to understand for people who doesn't study them. So don't use if you don't know how to use them @AntonSorokin and do never use the new Java features too.
  
  – Rhuan Karlus
  Mar 8 at 17:42
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @RhuanKarlus My message doesnt mean that I dont know lambda or I propose not to learn/use new language features. I meant that it is not necessary to use a complicated version when there is a simpler construction.
  
  – Anton Sorokin
  Mar 9 at 5:16
  

  
  
  
  

add a comment | 

Actually, using Java 8 you can use this by quite simple lambda solution:

final int[] numbs = 1, 3, 5, 7 ;
int index = 2;
IntStream.rangeClosed(index - 1, index + 1)
 .filter(idx -> idx != index && idx >= 0 && idx < numbs.length)
 .forEach(idx -> System.out.println(numbs[idx]));

But please, create a method that receives your array and index in order to reuse the code.

share|improve this answer

edited Mar 8 at 17:40

answered Mar 8 at 16:42

Rhuan KarlusRhuan Karlus

7151024

final int[] numbs = 1, 3, 5, 7 ;
int index = 2;
IntStream.rangeClosed(index - 1, index + 1)
 .filter(idx -> idx != index && idx >= 0 && idx < numbs.length)
 .forEach(idx -> System.out.println(numbs[idx]));

share|improve this answer

edited Mar 8 at 17:40

answered Mar 8 at 16:42

Rhuan KarlusRhuan Karlus

7151024

answered Mar 8 at 16:42

Rhuan KarlusRhuan Karlus

7151024

answered Mar 8 at 16:42

Rhuan KarlusRhuan Karlus

7151024