get a comma separated string using java stream

I have the following code using java Stream.

I am trying the get the function to build a string of value: "a,b" in this case.
however, the output (separatedByComma in this case) is always "b".

Could somebody shed some light please?

@Test

public void testJoin() {

    List<MOccS> occList = new ArrayList<> (  );

    MOccS mOccS = new MOccS ();

    mOccS.setOccSCd ( "1" );

    mOccS.setOccSNm ( "a" );

    occList.add ( mOccS );



    MOccS mOccS2 = new MOccS ();

    mOccS2.setOccSCd ( "2" );

    mOccS2.setOccSNm ( "b" );

    occList.add ( mOccS2 );





    List<String> strings = new ArrayList<> (  );

    strings.add ( "1" );

    strings.add ( "2" );



    String separatedByComma = "";

    for(String word: strings) {

        separatedByComma = occList.stream ()

                                  .filter ( occ -> word.equalsIgnoreCase ( occ.getOccSCd () ) )         

                                  .map ( occ -> occ.getOccSNm () )

                                  .collect ( Collectors.joining ( "," ) );

     }



     System.out.println (separatedByComma);

}





class MOccS{

    String occSCd;

    String occSNm;

    ...

    getter/setter

    ...

}

edited Nov 14 '18 at 8:39

Eran

284k37462551

asked Nov 14 '18 at 8:20

zaozaoer

72110

add a comment |

I have the following code using java Stream.

I am trying the get the function to build a string of value: "a,b" in this case.
however, the output (separatedByComma in this case) is always "b".

Could somebody shed some light please?

@Test

public void testJoin() {

    List<MOccS> occList = new ArrayList<> (  );

    MOccS mOccS = new MOccS ();

    mOccS.setOccSCd ( "1" );

    mOccS.setOccSNm ( "a" );

    occList.add ( mOccS );



    MOccS mOccS2 = new MOccS ();

    mOccS2.setOccSCd ( "2" );

    mOccS2.setOccSNm ( "b" );

    occList.add ( mOccS2 );





    List<String> strings = new ArrayList<> (  );

    strings.add ( "1" );

    strings.add ( "2" );



    String separatedByComma = "";

    for(String word: strings) {

        separatedByComma = occList.stream ()

                                  .filter ( occ -> word.equalsIgnoreCase ( occ.getOccSCd () ) )         

                                  .map ( occ -> occ.getOccSNm () )

                                  .collect ( Collectors.joining ( "," ) );

     }



     System.out.println (separatedByComma);

}





class MOccS{

    String occSCd;

    String occSNm;

    ...

    getter/setter

    ...

}

edited Nov 14 '18 at 8:39

Eran

284k37462551

asked Nov 14 '18 at 8:20

zaozaoer

72110

add a comment |

I have the following code using java Stream.

I am trying the get the function to build a string of value: "a,b" in this case.
however, the output (separatedByComma in this case) is always "b".

Could somebody shed some light please?

@Test

public void testJoin() {

    List<MOccS> occList = new ArrayList<> (  );

    MOccS mOccS = new MOccS ();

    mOccS.setOccSCd ( "1" );

    mOccS.setOccSNm ( "a" );

    occList.add ( mOccS );



    MOccS mOccS2 = new MOccS ();

    mOccS2.setOccSCd ( "2" );

    mOccS2.setOccSNm ( "b" );

    occList.add ( mOccS2 );





    List<String> strings = new ArrayList<> (  );

    strings.add ( "1" );

    strings.add ( "2" );



    String separatedByComma = "";

    for(String word: strings) {

        separatedByComma = occList.stream ()

                                  .filter ( occ -> word.equalsIgnoreCase ( occ.getOccSCd () ) )         

                                  .map ( occ -> occ.getOccSNm () )

                                  .collect ( Collectors.joining ( "," ) );

     }



     System.out.println (separatedByComma);

}





class MOccS{

    String occSCd;

    String occSNm;

    ...

    getter/setter

    ...

}

edited Nov 14 '18 at 8:39

Eran

284k37462551

asked Nov 14 '18 at 8:20

zaozaoer

72110

I have the following code using java Stream.

I am trying the get the function to build a string of value: "a,b" in this case.
however, the output (separatedByComma in this case) is always "b".

Could somebody shed some light please?

@Test

public void testJoin() {

    List<MOccS> occList = new ArrayList<> (  );

    MOccS mOccS = new MOccS ();

    mOccS.setOccSCd ( "1" );

    mOccS.setOccSNm ( "a" );

    occList.add ( mOccS );



    MOccS mOccS2 = new MOccS ();

    mOccS2.setOccSCd ( "2" );

    mOccS2.setOccSNm ( "b" );

    occList.add ( mOccS2 );





    List<String> strings = new ArrayList<> (  );

    strings.add ( "1" );

    strings.add ( "2" );



    String separatedByComma = "";

    for(String word: strings) {

        separatedByComma = occList.stream ()

                                  .filter ( occ -> word.equalsIgnoreCase ( occ.getOccSCd () ) )         

                                  .map ( occ -> occ.getOccSNm () )

                                  .collect ( Collectors.joining ( "," ) );

     }



     System.out.println (separatedByComma);

}





class MOccS{

    String occSCd;

    String occSNm;

    ...

    getter/setter

    ...

}

java java-8 java-stream

edited Nov 14 '18 at 8:39

Eran

284k37462551

asked Nov 14 '18 at 8:20

zaozaoer

72110

edited Nov 14 '18 at 8:39

Eran

284k37462551

asked Nov 14 '18 at 8:20

zaozaoer

72110

edited Nov 14 '18 at 8:39

Eran

284k37462551

edited Nov 14 '18 at 8:39

Eran

284k37462551

edited Nov 14 '18 at 8:39

Eran

284k37462551

asked Nov 14 '18 at 8:20

zaozaoer

72110

asked Nov 14 '18 at 8:20

zaozaoer

72110

asked Nov 14 '18 at 8:20

zaozaoer

72110

add a comment |

2 Answers
2

active

oldest

votes

Each iteration of your for loop overwrites the value of separatedByComma. The first iteration assigns the String "a" to it, and the second replaces it with "b".

You should Stream over the elements of the strings List in order to join the Strings that match each of them into a single output String:

String separatedByComma = 

    strings.stream()

           .flatMap(word -> occList.stream()

                                   .filter(occ -> word.equalsIgnoreCase (occ.getOccSCd()))

                                   .map (occ -> occ.getOccSNm()))

           .collect(Collectors.joining (","));

Output:

a,b

edited Nov 14 '18 at 8:41

answered Nov 14 '18 at 8:25

Eran

284k37462551

Thank you very much, your solution produces exactly what I needed.

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

In your loop for(String word: strings) you overwrite your separatedByComma variable.

edited Nov 14 '18 at 8:47

Ole V.V.

28.6k63352

answered Nov 14 '18 at 8:23

talex

11k1648

I think you are right, could you let me know how to fix it? sorry I am new to java stream...

– zaozaoer
Nov 14 '18 at 8:24

If you want to filter occList and allow only those which getOccSCd is in list of string I can give you code sample.

– talex
Nov 14 '18 at 8:26

thanks so much for your quick answer as well. It was very helpful!

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

Each iteration of your for loop overwrites the value of separatedByComma. The first iteration assigns the String "a" to it, and the second replaces it with "b".

You should Stream over the elements of the strings List in order to join the Strings that match each of them into a single output String:

String separatedByComma = 

    strings.stream()

           .flatMap(word -> occList.stream()

                                   .filter(occ -> word.equalsIgnoreCase (occ.getOccSCd()))

                                   .map (occ -> occ.getOccSNm()))

           .collect(Collectors.joining (","));

Output:

a,b

edited Nov 14 '18 at 8:41

answered Nov 14 '18 at 8:25

Eran

284k37462551

Thank you very much, your solution produces exactly what I needed.

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

Each iteration of your for loop overwrites the value of separatedByComma. The first iteration assigns the String "a" to it, and the second replaces it with "b".

You should Stream over the elements of the strings List in order to join the Strings that match each of them into a single output String:

String separatedByComma = 

    strings.stream()

           .flatMap(word -> occList.stream()

                                   .filter(occ -> word.equalsIgnoreCase (occ.getOccSCd()))

                                   .map (occ -> occ.getOccSNm()))

           .collect(Collectors.joining (","));

Output:

a,b

edited Nov 14 '18 at 8:41

answered Nov 14 '18 at 8:25

Eran

284k37462551

Thank you very much, your solution produces exactly what I needed.

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

Each iteration of your for loop overwrites the value of separatedByComma. The first iteration assigns the String "a" to it, and the second replaces it with "b".

You should Stream over the elements of the strings List in order to join the Strings that match each of them into a single output String:

String separatedByComma = 

    strings.stream()

           .flatMap(word -> occList.stream()

                                   .filter(occ -> word.equalsIgnoreCase (occ.getOccSCd()))

                                   .map (occ -> occ.getOccSNm()))

           .collect(Collectors.joining (","));

Output:

a,b

edited Nov 14 '18 at 8:41

answered Nov 14 '18 at 8:25

Eran

284k37462551

Each iteration of your for loop overwrites the value of separatedByComma. The first iteration assigns the String "a" to it, and the second replaces it with "b".

You should Stream over the elements of the strings List in order to join the Strings that match each of them into a single output String:

String separatedByComma = 

    strings.stream()

           .flatMap(word -> occList.stream()

                                   .filter(occ -> word.equalsIgnoreCase (occ.getOccSCd()))

                                   .map (occ -> occ.getOccSNm()))

           .collect(Collectors.joining (","));

Output:

a,b

edited Nov 14 '18 at 8:41

answered Nov 14 '18 at 8:25

Eran

284k37462551

edited Nov 14 '18 at 8:41

answered Nov 14 '18 at 8:25

Eran

284k37462551

answered Nov 14 '18 at 8:25

Eran

284k37462551

answered Nov 14 '18 at 8:25

Eran

284k37462551

Thank you very much, your solution produces exactly what I needed.

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

Thank you very much, your solution produces exactly what I needed.

– zaozaoer
Nov 14 '18 at 8:56

Thank you very much, your solution produces exactly what I needed.

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

In your loop for(String word: strings) you overwrite your separatedByComma variable.

edited Nov 14 '18 at 8:47

Ole V.V.

28.6k63352

answered Nov 14 '18 at 8:23

talex

11k1648

I think you are right, could you let me know how to fix it? sorry I am new to java stream...

– zaozaoer
Nov 14 '18 at 8:24

If you want to filter occList and allow only those which getOccSCd is in list of string I can give you code sample.

– talex
Nov 14 '18 at 8:26

thanks so much for your quick answer as well. It was very helpful!

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

In your loop for(String word: strings) you overwrite your separatedByComma variable.

edited Nov 14 '18 at 8:47

Ole V.V.

28.6k63352

answered Nov 14 '18 at 8:23

talex

11k1648

I think you are right, could you let me know how to fix it? sorry I am new to java stream...

– zaozaoer
Nov 14 '18 at 8:24

If you want to filter occList and allow only those which getOccSCd is in list of string I can give you code sample.

– talex
Nov 14 '18 at 8:26

thanks so much for your quick answer as well. It was very helpful!

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

In your loop for(String word: strings) you overwrite your separatedByComma variable.

edited Nov 14 '18 at 8:47

Ole V.V.

28.6k63352

answered Nov 14 '18 at 8:23

talex

11k1648

In your loop for(String word: strings) you overwrite your separatedByComma variable.

edited Nov 14 '18 at 8:47

Ole V.V.

28.6k63352

answered Nov 14 '18 at 8:23

talex

11k1648

edited Nov 14 '18 at 8:47

Ole V.V.

28.6k63352

edited Nov 14 '18 at 8:47

Ole V.V.

28.6k63352

edited Nov 14 '18 at 8:47

Ole V.V.

28.6k63352

answered Nov 14 '18 at 8:23

talex

11k1648

answered Nov 14 '18 at 8:23

talex

11k1648

answered Nov 14 '18 at 8:23

talex

11k1648

I think you are right, could you let me know how to fix it? sorry I am new to java stream...

– zaozaoer
Nov 14 '18 at 8:24

If you want to filter occList and allow only those which getOccSCd is in list of string I can give you code sample.

– talex
Nov 14 '18 at 8:26

thanks so much for your quick answer as well. It was very helpful!

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

I think you are right, could you let me know how to fix it? sorry I am new to java stream...

– zaozaoer
Nov 14 '18 at 8:24

If you want to filter occList and allow only those which getOccSCd is in list of string I can give you code sample.

– talex
Nov 14 '18 at 8:26

thanks so much for your quick answer as well. It was very helpful!

– zaozaoer
Nov 14 '18 at 8:56

I think you are right, could you let me know how to fix it? sorry I am new to java stream...

– zaozaoer
Nov 14 '18 at 8:24

If you want to filter occList and allow only those which getOccSCd is in list of string I can give you code sample.

– talex
Nov 14 '18 at 8:26

thanks so much for your quick answer as well. It was very helpful!

– zaozaoer
Nov 14 '18 at 8:56

add a comment |

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