The map.size() function in D3.js is used to return the number of entries in the created map.
Syntax:
map.size()
Parameters: This function does not accept any parameters.
Return Value: This function returns the number of entries in the created map.
Below programs illustrate the d3.map.size() function in D3.js:
Example 1:
javascript
<!DOCTYPE html> <html> <head> <title>d3.map.size() Function</title> </head> <body> <script> // Creating a map var map = d3.map({"Ram": 5, "Geeks": 10, "gfg": 15}); // Calling the map.size() function A = map.size(); // Getting the number of // entries in the map. console.log(A); </script> </body> </html> |
Output:
3
Example 2:
javascript
<!DOCTYPE html> <html> <head> <title>d3.map.size() Function</title> </head> <body> <script> // Creating some maps var map1 = d3.map({"Ram": 5}); var map2 = d3.map({"Geeks": 10}); var map3 = d3.map({"Ram": 5, "Geeks": 10}); var map4 = d3.map(); // Calling the map.size() function A = map1.size(); B = map2.size(); C = map3.size(); D = map4.size(); // Getting the number of entries in the map. console.log(A); console.log(B); console.log(C); console.log(D); </script> </body> </html> |
Output:
1 1 2 0
Ref: https://devdocs.io/d3~5/d3-collection#map_size