Simple is Beautiful.

References

How can I sort generic list DESC and ASC?

Sources

1. Use Linq

var ascendingOrder = li.OrderBy(i => i);

var descendingOrder = li.OrderByDescending(i => i);

2. Not use Linq

li.Sort((a, b) => a.CompareTo(b)); // ascending sort

li.Sort((a, b) => -1* a.CompareTo(b)); // descending sort

3. Make to list.

li = li.OrderBy(i => i).ToList();

References

How to find the Mode in Array C#? 

Sources

int mode = x.GroupBy(v => v).OrderByDescending(g => g.Count()).First().Key;

References

some 메서드(Array)(JavaScript)

Source

1. 배열내 모든 요소가 짝수인지 검사하기.

// The callback function.

function CheckIfEven(value, index, ar) {

    if (value % 2 == 0)

        return true;

}

var numbers = [1, 15, 4, 10, 11, 22];

var evens = numbers.some(CheckIfEven);

document.write(evens);

// Output:

// true

2. 기준값을 벗어나는 값이 있는지 검사하기

// Create a function that returns true if the value is 

// outside the range.

var isOutsideRange = function (value) {

    return value < this.minimum || value > this.maximum;

}

// Create an array of numbers.

var numbers = [6, 12, 16, 22, -12];

// The range object is to be the 'this' object.

var range = { minimum: 10, maximum: 20 };

document.write(numbers.some(isOutsideRange, range));

// Output: true

References 

[Javascript] 숫자 배열의 합을 찾는 방법

Sources

var sum = [1, 2, 3].reduce((a, b) => a + b, 0);

References 

Function.prototype.apply()

Source

/* min/max number in an array */

var numbers = [5, 6, 2, 3, 7];

/* using Math.min/Math.max apply */

var max = Math.max.apply(null, numbers); /* This about equal to Math.max(numbers[0], ...)

                                            or Math.max(5, 6, ...) */

var min = Math.min.apply(null, numbers);

/* vs. simple loop based algorithm */

max = -Infinity, min = +Infinity;

for (var i = 0; i < numbers.length; i++) {

  if (numbers[i] > max) {

    max = numbers[i];

  }

  if (numbers[i] < min) {

    min = numbers[i];

  }

}

References

javascript-배열을-스택처럼-다루기

Functions

var arr = [1, 2, 3];

//배열의 첫번째 원소 제거. (첫번째 원소 값을 리턴)

var head = arr.shift();          

//배열의 맨 앞에 1 추가.

arr.unshift(1);

//배열의 맨 뒤에 2 추가.

arr.push(2);

//배열의 마지막 원소 제거. (마지막 원소 값을 리턴)

vat tail = arr.pop();

Source

var s = 'abcABC';

var temp = s.split('');

s = temp.sort().reverse().join('');

Descriptions

.split()

string을 array로 변경

.sort()

배열을 정렬

.reverse()

정렬된 배열의 순서를 뒤집기

.join()

array타입을 string으로 변경

References

https://msdn.microsoft.com/ko-kr/library/7df7sf4x(v=vs.94).aspx

[자바스크립트] 동일한 단어를 문자열에서 찾기, Match() 함수

Sources

var src = "azcafAJAC";

var re = /[a-c]/;

var result = src.match(re);

// The entire match is in array element 0.

document.write(result[0] + "<br/>");

// Now try the same match with the global flag.

var reg = /[a-c]/g;

result = src.match(reg);

// The matches are in elements 0 through n.

for (var index = 0; index < result.length; index++)

{

    document.write ("submatch " + index + ": " +  result[index]);

    document.write("<br />");

}

Syntax

stringObj.match(rgExp) 

1. stringObj : 문자열

2. rgExp : 정규식 혹은 찾고자 할 문자열

Example

1. 

var str = 'red is impressive.'

str.match('red');

2.

var test  = 'love you. love me. love everything!'
var regExp = /love/gi;
test2 = test.match(regExp);

references : https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Array/filter

Source

var words = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];

const result = words.filter(word => word.length > 6);

console.log(result);

// expected output: Array ["exuberant", "destruction", "present"]

Example

function isBigEnough(value) {

  return value >= 10;

}

var filtered = [12, 5, 8, 130, 44].filter(isBigEnough);

// filtered: [12, 130, 44]

References : 외래키 조회

1. Query

SELECT uc.constraint_name, uc.table_name, ucc.column_name, uc.constraint_type, uc.r_constraint_name

FROM user_constraints uc, user_cons_columns ucc

WHERE uc.constraint_name = ucc.constraint_name;

2. Constraint_Type

 - P : Primary Key

 - R : Foreign Key

 - U : Unique

 - C : Not Null, Check