get salary greater than value along with their id

 create table emp(

id int auto_increment primary key,

salary float

)

insert into emp(salary) values(1000),(2000),(3000),(4000),(5000),(6000)

select * from emp;

select count(*),group_concat(id) from emp

where salary > 2000

Coding Interview Question : Output of Code snippet

What will be output of following code:

Example 1:

const b = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

for (let i = 0; i < 10; i++) {

setTimeout(() => console.log(b[i]), 1000);

}

for (var i = 0; i < 10; i++) {

setTimeout(() => console.log(b[i]), 1000);

}

output:

1

2

3

4

5

6

7

8

9

10

undefined

undefined

undefined

undefined

undefined

undefined

undefined

undefined

undefined

undefined

Pair of Socks problem on Hacker Rank

 

function PairOfSocks(arr) {

var obj = {}

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

if (obj[arr[i]] == undefined) {

obj[arr[i]] = 1

} else {

obj[arr[i]] = obj[arr[i]] + 1

}

}

var count = 0

for (var item in obj) {

var scount = Math.floor(obj[item] / 2)

count = count + scount

}

return count

}

var input = [1,2,1,2,1,3,2, 2, 0, 0]

var result = PairOfSocks(input)

console.log("result",result)

New Array methods in javascript

 let arr = ["sagar","sangram","sachin"]

//change element at specific index

var newArray = arr.with(0,"swapnil")

console.log("original:",arr)

console.log("new:",newArray)

//sort array and return sorted array but do not change original array

let sorted = arr.toSorted()

console.log("sorted:",sorted)

console.log("original:",arr)

//return reversed array but do not change original arary

let reveresed = arr.toReversed()

console.log("reveresed:",reveresed)

console.log("original:",arr)

//return spliced array but do not change original array

let spliced = arr.toSpliced(0,1)

console.log("spliced:",spliced)

console.log("original:",arr)

How to Remove Duplicate from Object Array:

let obj = [{ name: "sangram", age: 60 }, { name: "sangram", age: 60 }, { name: "sagar", age: 56 }, { name: "sagar", age: 56 }]

//method 1

var noduplicates = []

for (let i = 0; i < obj.length; i++) {

let entry = obj[i]

var index = obj.findIndex((t) => {

return t.name == entry.name && t.age == entry.age

})

if (index == i) {

noduplicates.push(entry)

}

}

console.log(noduplicates)

//more refine method

var nodup = obj.filter((entry, index, self) => {

return index == obj.findIndex((t) => {

return t.name == entry.name && t.age == entry.age

})

})

console.log(nodup)