The node.sum() function in d3.js is used to evaluate the specified value function for a particular node. The node.value property of this function contains the value returned by the specified function.
Syntax:
node.sum(value);
Parameters: This function accepts a single parameter as mentioned above and described below:
- value: This takes a function to be evaluated for each node.
Return Values: This function returns an object.
Below given are a few examples of the function given above.
Example 1:
HTML
<!DOCTYPE html> <html lang = "en"> <head> <meta charset = "UTF-8" /> <meta name = "viewport" path1tent = "width=device-width, initial-scale = 1.0"/> <script src = </script> </head> <body> <script> // Constructing a tree var tree={ name: "rootNode", // Root node children: [ { name: "child1", // Child of root node value: 2 }, { name: "child2", // Child of root node value: 3, children: [ { name: "grandchild1", // Child of child2 value: 1, children:[ {name: "grand_granchild1_1",value: 4}, // Child of grandchild1 {name: "grand_granchild1_2",value: 5} // Child of grandchild1 ] }, { name: "grandchild2", children:[ {name: "grand_granchild2_1"}, // Child of grandchild2 {name: "grand_granchild2_2"} // Child of grandchild2 ] }, ] } ] }; var obj = d3.hierarchy(tree); var grandchild2=obj.children[1].children[1]; var sum=obj.sum(d=>d.value); console.log(sum); console.log("The sum of value is: ",sum.value); </script> </body> </html> |
Output:
Example 2:
HTML
<!DOCTYPE html> <html lang = "en"> <head> <meta charset = "UTF-8" /> <meta name = "viewport" path1tent = "width=device-width, initial-scale = 1.0"/> <script src = </script> </head> <body> <script> // Constructing a tree var tree={ name: "rootNode", // Root node children: [ {value:1}, {value:2}, {value:3}, {value:4}, {value:5}, {value:6}, ] }; var obj = d3.hierarchy(tree); var sum=obj.sum(d=>d.value*12); // 1 + 2 + 3 + 4 + 5 + 6 = 21*12=252 console.log(sum); console.log("The value is: ",sum.value); </script> </body> </html> |
Output:
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