JavaScript dunyodagi eng mashhur dasturlash tili. JavaScript bu Internetning dasturlash tili

Original Value	Converted to Number	Converted to String	Converted to Boolean
Try it
false	0	"false"	false	Try it »
true	1	"true"	true	Try it »
0	0	"0"	false	Try it »
1	1	"1"	true	Try it »
"0"	0	"0"	true	Try it »
"000"	0	"000"	true	Try it »
"1"	1	"1"	true	Try it »
NaN	NaN	"NaN"	false	Try it »
Infinity	Infinity	"Infinity"	true	Try it »
-Infinity	-Infinity	"-Infinity"	true	Try it »
""	0	""	false	Try it »
"20"	20	"20"	true	Try it »
"twenty"	NaN	"twenty"	true	Try it »
[ ]	0	""	true	Try it »
[20]	20	"20"	true	Try it »
[10,20]	NaN	"10,20"	true	Try it »
["twenty"]	NaN	"twenty"	true	Try it »
["ten","twenty"]	NaN	"ten,twenty"	true	Try it »
function(){}	NaN	"function(){}"	true	Try it »
{ }	NaN	"[object Object]"	true	Try it »
null	0	"null"	false	Try it »
undefined	NaN	"undefined"	false	Try it »

Qo'shtirnoq ichidagi qiymatlar satr qiymatlarini bildiradi.
Qizil qiymatlar dasturchilar kutmagan qiymatlarni bildiradi (ba'zi).

JavaScript Bitwise operatsiyalari

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JavaScript Bitwise operatorlari

Operator	Name	Description
&	AND	Sets each bit to 1 if both bits are 1
|	OR	Sets each bit to 1 if one of two bits is 1
^	XOR	Sets each bit to 1 if only one of two bits is 1
~	NOT	Inverts all the bits
<<	Zero fill left shift	Shifts left by pushing zeros in from the right and let the leftmost bits fall off
>>	Signed right shift	Shifts right by pushing copies of the leftmost bit in from the left, and let the rightmost bits fall off
>>>	Zero fill right shift	Shifts right by pushing zeros in from the left, and let the rightmost bits fall off

Misollar

Operation	Result	Same as	Result
5 & 1	1	0101 & 0001	0001
5 | 1	5	0101 | 0001	0101
~ 5	10	~0101	1010
5 << 1	10	0101 << 1	1010
5 ^ 1	4	0101 ^ 0001	0100
5 >> 1	2	0101 >> 1	0010
5 >>> 1	2	0101 >>> 1	0010

JavaScript 32 bitli Bitwise Operands dan foydalanadi

JavaScript raqamlarni 64 bit suzuvchi nuqta raqamlari sifatida saqlaydi, ammo barcha bitli operatsiyalar 32 bitli ikkilik raqamlarda bajariladi.
Bitta operatsiya bajarilishidan oldin JavaScript raqamlarni 32 bit imzolangan butun songa o'zgartiradi.
Bit bitli operatsiya bajarilgandan so'ng, natija yana 64 bitli JavaScript raqamlariga o'tkaziladi.
Yuqoridagi misollarda 4 bit imzosiz ikkilik raqamlardan foydalaniladi. Shuning uchun ~ 5 10 ga qaytadi.
JavaScript-da 32 bit imzolangan tamsayı ishlatilganligi sababli, u 10 ga qaytmaydi.
000000000000000000000000000000001 (5)
11111111111111111111111111111010 (~ 5 = -6)
Imzo qo'yilgan butun son minus belgisi sifatida eng chap bitdan foydalanadi.

Bitwise va

Agar bitli VA bit bitida bajarilsa, ikkala bit ham 1 bo'lsa, u 1 ni qaytaradi.
Bitta misol:

Ishlash	Natija
0 va 0	0
0 va 1	0
1 va 0	0
1 va 1	1

4 bitli misol:

Ishlash	Natija
1111 va 0000	0000
1111 va 0001	0001
1111 va 0010	0010
1111 va 0100	0100

Yagona yoki

Bit juftlik ustida bitli OR bajarilganda, bitlardan biri 1 bo'lsa, u 1 ga qaytadi:
Bitta misol:

Ishlash	Natija
0 | 0	0
0 | 1	1
1 | 0	1
1 | 1	1

4 bitli misol:

Ishlash	Natija
1111 | 0000	1111
1111 | 0001	1111
1111 | 0010	1111
1111 | 0100	1111

Bitorli XOR

Bit bitli XOR bit bitida bajarilganda, bitlar boshqacha bo'lsa, u 1 ga qaytadi:
Bitta misol:

Ishlash	Natija
0 ^ 0	0
0 ^ 1	1
1 ^ 0	1
1 ^ 1	0

4 bitli misol:

Ishlash	Natija
1111 ^ 0000	1111
1111 ^ 0001	1110
1111 ^ 0010	1101
1111 ^ 0100	1011

JavaScript Bitwise VA (&)

Bitwise AND har ikkala bit ham 1 bo'lgan taqdirda 1 ni qaytaradi:

O'nli	Ikkilik
5	0000000000000000000000000000000101
1	0000000000000000000000000000000001
5 va 1	0000000000000000000000000000000001 (1)

Misol

var x = 5 & 1;
O'zingiz sinab ko'ring »

JavaScript Bitwise YOKI (|)

Bit bitli OR, agar bitlardan biri 1 bo'lsa, 1 qaytaradi

O'nli	Ikkilik
5	0000000000000000000000000000000101
1	0000000000000000000000000000000001
5 | 1	000000000000000000000000000000001 (5)

Misol

var x = 5 | 1;
O'zingiz sinab ko'ring »

JavaScript Bitwise XOR (^)

Bitwise XOR, agar bitlar boshqacha bo'lsa, 1ni qaytaradi:

O'nli	Ikkilik
5	0000000000000000000000000000000101
1	0000000000000000000000000000000001
5 ^ 1	00000000000000000000000000000000100 (4)

Misol

var x = 5 ^ 1;
O'zingiz sinab ko'ring »

JavaScript Bitwise EMAS (~)

O'nli	Ikkilik
5	0000000000000000000000000000000101
~ 5	1111111111111111111111111111111010 (-6)

Misol

var x = ~5;
O'zingiz sinab ko'ring »

JavaScript (nol bilan to'ldirish) chapga chapga siljish (<<)

Bu chapga siljishni nol bilan to'ldirish. Bir yoki bir nechta nol bitlar o'ng tomondan itariladi va eng chap bitlar tushadi:

O'nli	Ikkilik
5	0000000000000000000000000000000101
5 << 1	0000000000000000000000000000001010 (10)

Misol

var x = 5 << 1;
O'zingiz sinab ko'ring »

JavaScript (Belgilarni saqlash) Bitwise o'ngga siljish (>>)

Bu to'g'ri siljishni saqlaydigan belgidir. Eng chap qismning nusxalari chap tomondan suriladi va eng o'ng bitlar tushadi:

O'nli	Ikkilik
-5	1111111111111111111111111111111011
-5 >> 1	1111111111111111111111111111111101 (-3)

Misol

var x = -5 >> 1;
O'zingiz sinab ko'ring »

JavaScript (Zero Fill) O'ngga o'tish (>>>)

Bu nolni to'ldirish o'ngga siljish. Bitta yoki bir nechta nol bit chapdan suriladi va eng o'ng bitlar tushadi:

O'nli	Ikkilik
5	0000000000000000000000000000000101
5 >>> 1	0000000000000000000000000000000010 (2)

Misol

var x = 5 >>> 1;
O'zingiz sinab ko'ring »

Ikkilik raqamlar

Bitta bitli ikkilik raqamlarni tushunish oson:

Ikkilik vakillik	O'nli qiymat
0000000000000000000000000000000001	1
000000000000000000000000000000000010	2018-04-02 121 2
0000000000000000000000000000000100	4
0000000000000000000000000000001000	8
00000000000000000000000000010000	16
00000000000000000000000000100100000	32
00000000000000000000000001000000	64

Yana bir nechta bitni o'rnatish ikkilik naqshni ko'rsatadi:

Ikkilik vakillik	O'nli qiymat
0000000000000000000000000000000101	5 (4 + 1)
0000000000000000000000000000001101	13 (8 + 4 + 1)
0000000000000000000000000010101010	45 (32 + 8 + 4 + 1)

JavaScript-ning ikkilik raqamlari ikkitaning qo'shimcha shaklida saqlanadi.
Bu shuni anglatadiki, manfiy son plyus 1 sonining bittasi YO'Q:

Ikkilik vakillik	O'nli qiymat
0000000000000000000000000000000101	5
1111111111111111111111111111111011	-5
0000000000000000000000000000000110	6
1111111111111111111111111111111010	-6
0000000000000000000000000010101000	40
11111111111111111111111111011000	-40

O'nlikni ikkilikka aylantirish

Misol

function dec2bin(dec){
return (dec >>> 0).toString(2);
}
O'zingiz sinab ko'ring »

Ikkilikni o'nlikka aylantirish

Misol

function bin2dec(bin){
return parseInt(bin, 2).toString(10);
}

JavaScript muntazam iboralari

❮ OldingiKeyingi ❯
Doimiy ifoda - bu izlash naqshini shakllantiruvchi belgilar ketma-ketligi.
Qidiruv naqshidan matnni qidirish va matnni almashtirish operatsiyalari uchun foydalanish mumkin.

Muntazam ifoda nima?

Doimiy ifoda - bu izlash naqshini shakllantiruvchi belgilar ketma-ketligi .
Matndagi ma'lumotlarni qidirishda ushbu qidiruv sxemasidan nimani qidirayotganingizni tasvirlash uchun foydalanishingiz mumkin.
Muntazam ibora bitta belgi yoki murakkabroq naqsh bo'lishi mumkin.
Matnni izlash va matnni almashtirish operatsiyalarining barcha turlarini bajarish uchun odatiy iboralardan foydalanish mumkin .

Sintaksis

/pattern/modifiers;

Misol

var patt = /w3schools/i;
Misol tushuntirildi:
/ w3schools / i doimiy iboradir.
w3schools - bu naqsh (qidirishda foydalanish uchun).
i modifikator (qidiruvni katta-kichikligiga qarab o'zgartiradi).

String usullaridan foydalanish

JavaScript-da odatiy iboralar ko'pincha ikkita satr usuli bilan ishlatiladi : search()va replace().
search()Usuli o'yinda qo'ng'iroq qilish uchun bir iborani ishlatadi, va o'yin o'rnini qaytaradi.
replace()Usuli namuna o'rnini bir tahrirlangan mag'lubiyatga qaytaradi.

String yordamida String search () dan foydalanish

search()Usul izlaydi, bir belgilangan qiymat va qaytib o'yinda pozitsiyasi uchun string:

Misol

Qatorda "W3schools" ni qidirish uchun satrdan foydalaning:
var str = "Visit W3Schools!";
var n = str.search("W3Schools");
O'zingiz sinab ko'ring »

String search () dan odatiy ifoda bilan foydalanish

Misol

"W3schools" qatorini kichik harflar bilan qidirish uchun oddiy iboradan foydalaning:
var str = "Visit W3Schools";
var n = str.search(/w3schools/i);
N natija quyidagicha bo'ladi:
6
O'zingiz sinab ko'ring »

String-ni almashtirish () -ni String bilan ishlatish

replace()Usuli bilan mag'lubiyatga boshqa qiymati bilan belgilangan qiymat o'rnini:
var str = "Visit Microsoft!";
var res = str.replace("Microsoft", "W3Schools");
O'zingiz sinab ko'ring »

String-dan foydalaning () muntazam ifodasi bilan

Misol

Bir qatorda Microsoft-ni W3Schools bilan almashtirish uchun harfga sezgir bo'lmagan doimiy ifodadan foydalaning:
var str = "Visit Microsoft!";
var res = str.replace(/microsoft/i, "W3Schools");
Natija quduq sohiblari bo'ladi:
Visit W3Schools!
O'zingiz sinab ko'ring »

E'tibor berganmisiz?

Muntazam ifoda argumentlari (satr argumentlari o'rniga) yuqoridagi usullarda ishlatilishi mumkin.
Muntazam iboralar sizning qidiruvingizni yanada kuchliroq qilishi mumkin (masalan, harflar sezgir emas).

Muntazam ifoda o'zgartirgichlari

Modifikatorlardan katta-kichik global qidiruvlarni amalga oshirish uchun foydalanish mumkin:

Modifier	Description	Try it
i	Perform case-insensitive matching	Try it »
g	Perform a global match (find all matches rather than stopping after the first match)	Try it »
m	Perform multiline matching	Try it »

Muntazam ifoda namunalari

Qavslar bir qator belgilarni topish uchun ishlatiladi:

Expression	Description	Try it
[abc]	Find any of the characters between the brackets	Try it »
[0-9]	Find any of the digits between the brackets	Try it »
(x|y)	Find any of the alternatives separated with |	Try it »

Metakarakterlar - bu alohida ma'noga ega bo'lgan belgilar:

Metacharacter	Description	Try it
\d	Find a digit	Try it »
\s	Find a whitespace character	Try it »
\b	Find a match at the beginning of a word like this: \bWORD, or at the end of a word like this: WORD\b	Try it » Try it »
\uxxxx	Find the Unicode character specified by the hexadecimal number xxxx	Try it »

Quantifiers miqdorda aniqlash:

Quantifier	Description	Try it
n+	Matches any string that contains at least one n	Try it »
n*	Matches any string that contains zero or more occurrences of n	Try it »
n?	Matches any string that contains zero or one occurrences of n	Try it »

RegExp ob'ektidan foydalanish

JavaScript-da, RegExp ob'ekti oldindan belgilangan xususiyatlar va usullarga ega bo'lgan muntazam ekspression ob'ekti.

Test () dan foydalanish

test()Usul RegExp ifoda usuli hisoblanadi.
U naqshni izlaydi va natijaga qarab true yoki false qiymatini qaytaradi.
Quyidagi misol "e" belgisi uchun satrni izlaydi:

Misol

var patt = /e/;
patt.test("The best things in life are free!");
Satrda "e" bo'lganligi sababli yuqoridagi kodning chiqishi quyidagicha bo'ladi:
true
O'zingiz sinab ko'ring »
Avval doimiy o'zgaruvchini o'zgaruvchiga qo'yishingiz shart emas. Yuqoridagi ikkita satrni biriga qisqartirish mumkin:
/e/.test("The best things in life are free!");

Exec () dan foydalanish

exec()Usul RegExp ifoda usuli hisoblanadi.
U belgilangan naqshni izlaydi va topilgan matnni ob'ekt sifatida qaytaradi.
Agar mos keladigan narsa topilmasa, u bo'sh (null) ob'ektni qaytaradi .
Quyidagi misol "e" belgisi uchun satrni izlaydi:

1-misol

/e/.exec("The best things in life are free!");
O'zingiz sinab ko'ring »

To'liq RegExp ma'lumotnomasi

To'liq ma'lumot olish uchun to'liq JavaScript RegExp ma'lumotnomamizga o'ting .
Ma'lumotnomada barcha RegExp xususiyatlari va usullarining tavsiflari va misollari mavjud.