Operation on Objects

The following operations are performed on the previously created vector v1 of type DOUBLE.

Appending Elements

// append a single element
v1->append(new Double(1.5));   // v1: [1.1,2.2,3.3,1.5]
// append 3 elements
v1->append(new Double(2), 3);  // v1: [1.1,2.2,3.3,1.5,2,2,2]

Accessing Elements

ConstantSP e1 = v1->get(0);     // obtain the first element
double e2 = v1->getDouble(1);   // obtain the second element

Updating Vectors

// update the second element with value 100
v1->set(1, new Double(100));  // vi: [1.1,100,3.3,1.5,2,2,2]

Deleting Elements

// remove element in specific position
ConstantSP index = Util::createIndexVector(3, 1);
v1->remove(index);     vi: [1.1,100,3.3,2,2,2]

// remove the last 4 elements
v1->remove(4);    // [1.1,100]

The following operations are performed on the previously created table tb1.

Accessing Tables by Column

// obtain the first column
VectorSP col1 = tb1->getColumn(0);    // [0,1,2,3,4,5,6,7,8,9]

// obtain the column val
VectorSP col2 = tb1->getColumn("val");   //[0,1.1,2.2,3.3,4.400000000000001,5.5,6.600000000000001,7.700000000000001,8.8,9.9]

Accessing Tables by Row

// obtain the first row
DictionarySP row = tb1->get(0);     
std::cout << row->getString() << std::endl;  

/* output：
id->0
val->0
*/

Appending Records

INDEX insertedRows;     
std::string errorMsg;     
VectorSP col0 = Util::createVector(DT_INT, 0);     
VectorSP col1 = Util::createVector(DT_DOUBLE, 0);       
col0->append(new Int(20));     
col1->append(new Double(30.5));     
vector<ConstantSP> values{col0, col1};     
tb1->append(values, insertedRows, errorMsg); 
std::cout << tb1->getString() << std::endl;  

/* output:
id val              
-- -----------------
0  0                
1  1.1              
2  2.2              
3  3.3              
4  4.400000000000001
5  5.5              
6  6.600000000000001
7  7.700000000000001
8  8.8              
9  9.9              
20 30.5    
*/

Updating Records

VectorSP col1 = tb1->getColumn(0);    
VectorSP col2 = tb1->getColumn("val");  

// update the third row by updating the third element of each column 
col1->set(2, new Int(100));
col2->set(2, new Double(32.597));

std::cout << tb1->getString() << std::endl;   

/* output：
id  val               
--- ------------------
0   0                 
1   1.1               
100 32.597000000000001
3   3.3               
4   4.400000000000001 
5   5.5               
6   6.600000000000001 
7   7.700000000000001 
8   8.8               
9   9.9   
*/