Array 메소드

1. Array.map()

var numbers1 = [10, 20, 30, 40, 50];

var numbers3 = numbers1.map(function(value, index, array){

return value * 3;

});

 

30,60,90,120,150

 

2. Array.filter()

var numbers = [50, 25, 40, 16, 29];

var numOver30 = numbers.filter(function(value, index, array){

return value > 30;

});

 

50,40

 

3. Array.forEach()

var prntVal = "";

var names = ['Frank', 'Charles', 'Dolly', 'Robert', 'Bob'];

names.forEach(function(value){

prntVal = prntVal + 'Hello '+ value +"<br/>";

});

 

Hello Frank

Hello Charles

Hello Dolly

Hello Robert

Hello Bob

 

4. Array.reduce()

var nums = [10, 20, 30, 40, 50];

var sum = nums.reduce(function(total, value){

return total + value;

});

 

150

 

5. Array.redcueRight()

var nums = [10, 20, 30, 40, 50];

var sum = nums.reduceRight(function(total, value){

return total + value;

});

 

150

 

6. Array.some()

var nums = [10, 20, 30, 40, 50];

var over30 = nums.some(function(value){

return value > 30;

});

 

true

 

7. Array.every()

var nums = [10, 20, 30, 40, 50];

var Allover30 = nums.every(function(value){

return value > 30;

});

 

false

 

8. Array.find()

var nums = [10, 20, 30, 40, 50];

var firstNum = nums.find(function(value){

return value > 30

});

 

40

 

9. Array.findIndex()

var nums = [10, 20, 30, 40, 50];

var findNumIndex = nums.findIndex(function(value){

return value > 30

});

 

3

 

10. Array.indexOf()

var names = ['Frank', 'Charles', 'Dolly', 'Robert', 'Bob'];

var pos = names.indexOf("Dolly");

 

2

 

11. Array.lastIndexOf()

var names = ['Frank', 'Charles', 'Dolly', 'Robert', 'Bob'];

var pos = names.lastIndexOf("Charles");

 

1