List<List<String>> with filter-CodePudding

I have a list which contains another list Which has String values

[ 
 ["ax", "BX", "CX_123"],
 ["ax", "BX", "CD_124"],
 ["ax", "BX", "CY_456"]
],
[ 
 ["ax", "BX", "CB_456"],
 ["ax", "BX", "CX_564"],
 ["ax", "BX", "CZ_345"]
],[ 
 ["ax", "BX", "CE_234"],
 ["ax", "BX", "CM_235"],
 ["ax", "BX", "CX_4534"]
]

I have to filter the list which start with CX_ value in the inner list

The result should look like:

[
   ["ax", "BX", "CX_123"],
   ["ax", "BX", "CX_564"],
   ["ax", "BX", "CX_4534"]
]

CodePudding user response：

You can use stream and filter to retrieve the result with condition

@Test
  public void test() {
    List<String> row1 = Arrays.asList("AA","BB","CX_11");
    List<String> row2 = Arrays.asList("CC","D","CD_11");
    List<List<String>> list = Arrays.asList(row1,row2);
    Assertions.assertEquals(row1, getFirstList(list,"CX_"));
    Assertions.assertEquals(row2, getFirstList(list,"CD_"));
  }

  public List<List<String>> getAllList(List<List<String>> list,String key){
    return list.stream().filter(this.contain(key)).collect(Collectors.toList());
  }
  
  public List<Map<String,String>> getListOfMap(List<List<String>> list,String key){
    Function<List<String>,Map<String,String>> convertListToMap = (l)->{
      Map<String,String> map = new LinkedHashMap<>();
      map.put("name", l.get(1));
      map.put("code", l.get(2));
      return map;
    }; 
    return list.stream().filter(this.contain(key)).map(convertListToMap).collect(Collectors.toList());
  }
  
  public List<String> getFirstList(List<List<String>> list,String key){
    return list.stream().filter(this.contain(key)).findFirst().get();
  }
  
  private Predicate<List<String>> contain(String key){
    return (l)-> l.stream().anyMatch(s-> s.contains(key));
  }

CodePudding user response：

You can do it by the following steps:
1. Declare a List<List<String>> will be returned
2. Foreach List<List<String>>, fetch each List<String>
       2.1. With each List<String>, foreach it, fetch each string
       2.2. If each string contains CX_ value, add this List<String> to the returned List<List<String>>