Array Methods You Must Know

Introduction

Arrays sirf values store karne ke liye useful nahi hoti.

Real power tab aati hai jab hum un arrays ke saath kaam karna start karte hain.

For example:

• new item add karna

• last item remove karna

• har element ko update karna

• kuch specific values nikalna

• total sum calculate karna

Yahi kaam array methods ke through easy ho jaata hai.

Simple words mein:

array methods built-in functions hoti hain jo array par common operations perform karne mein help karti hain

Har method ka apna role hota hai.

• kuch methods original array ko change karti hain

• kuch methods new array return karti hain

• aur kuch methods sirf har item par kaam karne ke liye use hoti hain

push() and pop()

Ye dono methods array ke end ke saath kaam karti hain.

Jab humein last mein new value add karni ho, tab push() useful hota hai. Jab humein last value remove karni ho, tab pop() useful hota hai.

push()

let fruits = ["Apple", "Banana"];
fruits.push("Mango");
console.log(fruits);

Yahan "Mango" array ke end mein add ho gaya.

pop()

let fruits = ["Apple", "Banana", "Mango"];
fruits.pop();
console.log(fruits);

Yahan last item remove ho gaya.

shift() and unshift()

Ye methods bhi add/remove ka kaam karti hain, but difference ye hai ki ye array ke start se kaam karti hain.

shift()

let fruits = ["Apple", "Banana", "Mango"];
fruits.shift();
console.log(fruits);

shift() first element ko remove karta hai.

unshift()

let fruits = ["Banana", "Mango"];
fruits.unshift("Apple");
console.log(fruits);

unshift() first position par new value add karta hai.

forEach()

forEach() tab useful hota hai jab humein array ke har element ke saath koi action perform karna ho.

Ye mostly tab use hota hai jab humein:

• print karna ho

• value inspect karni ho

• simple side effect run karna ho

let numbers = [2, 4, 6];

numbers.forEach((num) => {
  console.log(num);
});

Traditional loop ke comparison mein ye cleaner lag sakta hai for simple iteration.

Important point:

forEach() new array return nahi karta. Ye sirf har element par kaam chalata hai.

map()

map() tab use hota hai jab humein existing array ke har element ko transform karke ek new array banana ho.

Yani original data same reh sakta hai, aur transformed result alag mil jaata hai.

let numbers = [2, 4, 6];

let doubled = numbers.map((num) => {
  return num * 2;
});

console.log(doubled);

map() har element ko transform karta hai aur new array return karta hai.

Yahan:

• 2 becomes 4

• 4 becomes 8

• 6 becomes 12

filter()

filter() tab useful hota hai jab humein array mein se sirf kuch selected values rakhni ho.

Ye har element par condition check karta hai. Jo value condition pass karti hai, woh new array mein chali jaati hai.

let numbers = [5, 12, 18, 7];

let greaterThan10 = numbers.filter((num) => {
  return num > 10;
});

console.log(greaterThan10);

filter() sirf matching values ko new array mein rakhta hai.

Is example mein sirf 12 aur 18 condition pass karte hain.

reduce() - Basic Explanation

reduce() beginner ko pehle thoda tricky lag sakta hai, but idea simple hai.

Ye array ki multiple values ko step by step process karke ek final result banata hai.

Ye final result ho sakta hai:

• total sum

• product

• count

• ek single combined value

let numbers = [10, 20, 30];

let total = numbers.reduce((sum, num) => {
  return sum + num;
}, 0);

console.log(total);

reduce() many values ko ek final result mein combine karta hai.

Is example mein:

• pehle 0 + 10

• phir result + 20

• phir result + 30

Final answer 60 aata hai.

A Small Practice Assignment

Is small practice ka goal ye hai ki tum teen different methods ka role ek saath compare kar sako:

• map() transformation ke liye

• filter() selection ke liye

• reduce() final calculation ke liye

let numbers = [5, 10, 15, 20];

let doubled = numbers.map((num) => num * 2);
console.log(doubled);

let greaterThan10 = numbers.filter((num) => num > 10);
console.log(greaterThan10);

let total = numbers.reduce((sum, num) => sum + num, 0);
console.log(total);

Expected understanding:

• doubled mein har value double ho jaayegi

• greaterThan10 mein sirf 10 se badi values rahengi

• total mein sab numbers ka sum aayega

Summary

• push() array ke end mein value add karta hai

• pop() end se value remove karta hai

• shift() start se remove karta hai

• unshift() start mein add karta hai

• forEach() har element par action perform karta hai

• map() transformed new array banata hai

• filter() matching values ki new array banata hai

• reduce() many values ko one final result mein combine karta hai

Final Thought

Array methods JavaScript ko zyada expressive aur readable banati hain.

Ek baar inka basic use samajh aa gaya, toh arrays ke saath kaam karna kaafi smoother lagne lagta hai.

Continue Reading

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