객체와 문자배열

객체 생성

// without instance
var str1 = 'Hello JavaScript';
console.log(str1.length);

var bool1 = true;
console.log(bool1);

var num1 = 10;
console.log(num1);

console.log('\n');

// wrapper
var str2 = new String('Hello JavaScript');
console.log(str2.length);

var bool2 = new Boolean(false);
console.log(bool2);

var num2 = new Number(10);
console.log(num2);

문자열 나누기

var str1 = 'Good day to study day the javascript day!';

console.log(str1.indexOf('day'));
console.log(str1.lastIndexOf('day'));
console.log(str1.indexOf('day', 10));
console.log(str1.lastIndexOf('day', 10));
console.log(str1.indexOf('hello'));

var str2 = 'Circulus Project';

console.log(str2.charAt(5)); // "l";
console.log(str2.slice(5, 8)); // "lus"
console.log(str2.substring(5, 8)); // "lus"
console.log(str2.substr(5, 8)); // "lus Proj"
console.log(str2.split('u')); // ["Circ", "l", "s Project"]
console.log(str1.split('day', 3)); // ["Good", "to study", "the javscript"]
console.log(str1.split('day')); // ["Good", "to study", "the javscript", "!"]

console.log('upper'.anchor('top'));
console.log(str2.link('http://www.circul.us'));

console.log('10'.sub());
console.log('10'.sup());

console.log(str2.concat('thanks'));
console.log(str2.length);

NaN

var num1 = 123;

var num2 = new Number(123);
console.log(num1 + num2);

var num3 = 255;
console.log(num3.toString());
console.log(num3.toString(16));
console.log(num3.toString(8));

var num4 = 123.45678;  

console.log(num4.toExponential(2));
console.log(num4.toFixed(3));
console.log(num4.toFixed(7));
console.log(num4.toPrecision(10));
console.log(num4.toPrecision(6));


// NaN = Not a Number
console.log(0 / 0);
console.log(Number.NaN == Number.NaN);
console.log(isNaN(Number.NaN));

var num = 10;
var num2 = '10';
var num3 = 'test';
console.log(isNaN(num));
console.log(isNaN(num2));
console.log(isNaN(num3));

Math

// Math
console.log(Math.abs(-15));
console.log(Math.max(10, 15));
console.log(Math.min(-10, 0));
console.log(Math.pow(2, 3));
console.log(Math.random());
console.log(Math.ceil(1, 58));
console.log(Math.floor(1, 58));
console.log(Math.round(1, 58));
console.log(Math.PI);
console.log(Math.floor((Math.random() * 10) + 1));

Array

var a = new Array('A', 'B', 'C');
console.log(a);
var b = new Array(2);
console.log(b);

var arr1 = ['Tomato', 'Apple', 'Blueberry', 'Orange', 'Melon'];
var arr2 = ['Mozart', 'schuberry', 'Bach'];

console.log(arr1.concat(arr2));
console.log(arr1.join('_'));
console.log(arr1.splice(1));
console.log('---');
console.log(arr1.splice(1, 2));
console.log(arr1.splice(1, 2, 'strawberry', 'fineapple'));
console.log('---');
console.log(arr1);
console.log(arr1.pop());
console.log(arr1);

정렬

console.log(arr1);
console.log(arr1.push('Strawberry'));
console.log(arr1);
console.log(arr1.shift()); // remove a first one
console.log(arr1);
console.log(arr1.unshift('Strawberry', 'fineapple'));
console.log(arr1);
console.log(arr1.reverse());
console.log(arr1.sort());
console.log(arr1.length);
console.log(arr1.toString());

var arr3 = [5, 25, 10];
console.log(arr3);
console.log(arr3.sort());
console.log(arr3.sort(function(x, y){
    return x - y;
}));

console.log(arr3.sort(function(x, y){
    return y - x;
}))