How do I convert a string to an integer in JavaScript?
The simplest way would be to use the native Number function:
var x = Number("1000")
If that doesn't work for you, then there are the parseInt, unary plus, parseFloat with floor, and Math.round methods.
parseInt()
var x = parseInt("1000", 10); // You want to use radix 10
// So you get a decimal number even with a leading 0 and an old browser ([IE8, Firefox 20, Chrome 22 and older][1])
Unary plus
If your string is already in the form of an integer:
var x = +"1000";
floor()
If your string is or might be a float and you want an integer:
var x = Math.floor("1000.01"); // floor() automatically converts string to number
Or, if you're going to be using Math.floor several times:
var floor = Math.floor;
var x = floor("1000.01");
parseFloat()
If you're the type who forgets to put the radix in when you call parseInt, you can use parseFloat and round it however you like. Here I use floor.
var floor = Math.floor;
var x = floor(parseFloat("1000.01"));
round()
Interestingly, Math.round (like Math.floor) will do a string to number conversion, so if you want the number rounded (or if you have an integer in the string), this is a great way, maybe my favorite:
var round = Math.round;
var x = round("1000"); // Equivalent to round("1000", 0)
Try parseInt function:
var number = parseInt("10");
But there is a problem. If you try to convert "010" using parseInt function, it detects as octal number, and will return number 8. So, you need to specify a radix (from 2 to 36). In this case base 10.
parseInt(string, radix)
Example:
var result = parseInt("010", 10) == 10; // Returns true
var result = parseInt("010") == 10; // Returns false
Note that parseInt ignores bad data after parsing anything valid.
This guid will parse as 51:
var result = parseInt('51e3daf6-b521-446a-9f5b-a1bb4d8bac36', 10) == 51; // Returns true
There are two main ways to convert a string to a number in JavaScript. One way is to parse it and the other way is to change its type to a Number. All of the tricks in the other answers (e.g., unary plus) involve implicitly coercing the type of the string to a number. You can also do the same thing explicitly with the Number function.
Parsing
var parsed = parseInt("97", 10);
parseInt and parseFloat are the two functions used for parsing strings to numbers. Parsing will stop silently if it hits a character it doesn't recognise, which can be useful for parsing strings like "92px", but it's also somewhat dangerous, since it won't give you any kind of error on bad input, instead you'll get back NaN unless the string starts with a number. Whitespace at the beginning of the string is ignored. Here's an example of it doing something different to what you want, and giving no indication that anything went wrong:
var widgetsSold = parseInt("97,800", 10); // widgetsSold is now 97
It's good practice to always specify the radix as the second argument. In older browsers, if the string started with a 0, it would be interpreted as octal if the radix wasn't specified which took a lot of people by surprise. The behaviour for hexadecimal is triggered by having the string start with 0x if no radix is specified, e.g., 0xff. The standard actually changed with ECMAScript 5, so modern browsers no longer trigger octal when there's a leading 0 if no radix has been specified. parseInt understands radixes up to base 36, in which case both upper and lower case letters are treated as equivalent.
Changing the Type of a String to a Number
All of the other tricks mentioned above that don't use parseInt, involve implicitly coercing the string into a number. I prefer to do this explicitly,
var cast = Number("97");
This has different behavior to the parse methods (although it still ignores whitespace). It's more strict: if it doesn't understand the whole of the string than it returns NaN, so you can't use it for strings like 97px. Since you want a primitive number rather than a Number wrapper object, make sure you don't put new in front of the Number function.
Obviously, converting to a Number gives you a value that might be a float rather than an integer, so if you want an integer, you need to modify it. There are a few ways of doing this:
var rounded = Math.floor(Number("97.654")); // other options are Math.ceil, Math.round
var fixed = Number("97.654").toFixed(0); // rounded rather than truncated
var bitwised = Number("97.654")|0; // do not use for large numbers
Any bitwise operator (here I've done a bitwise or, but you could also do double negation as in an earlier answer or a bit shift) will convert the value to a 32 bit integer, and most of them will convert to a signed integer. Note that this will not do want you want for large integers. If the integer cannot be represented in 32 bits, it will wrap.
~~"3000000000.654" === -1294967296
// This is the same as
Number("3000000000.654")|0
"3000000000.654" >>> 0 === 3000000000 // unsigned right shift gives you an extra bit
"300000000000.654" >>> 0 === 3647256576 // but still fails with larger numbers
To work correctly with larger numbers, you should use the rounding methods
Math.floor("3000000000.654") === 3000000000
// This is the same as
Math.floor(Number("3000000000.654"))
Bear in mind that coercion understands exponential notation and Infinity, so 2e2 is 200 rather than NaN, while the parse methods don't.
Custom
It's unlikely that either of these methods do exactly what you want. For example, usually I would want an error thrown if parsing fails, and I don't need support for Infinity, exponentials or leading whitespace. Depending on your use case, sometimes it makes sense to write a custom conversion function.
Always check that the output of Number or one of the parse methods is the sort of number you expect. You will almost certainly want to use isNaN to make sure the number is not NaN (usually the only way you find out that the parse failed).
ParseInt() and + are different
parseInt("10.3456") // returns 10
+"10.3456" // returns 10.3456
Fastest
var x = "1000"*1;
Test
Here is little comparison of speed (macOS only)... :)
For Chrome, 'plus' and 'mul' are fastest (>700,000,00 op/sec), 'Math.floor' is slowest. For Firefox, 'plus' is slowest (!) 'mul' is fastest (>900,000,000 op/sec). In Safari 'parseInt' is fastest, 'number' is slowest (but results are quite similar, >13,000,000 <31,000,000). So Safari for cast string to int is more than 10x slower than other browsers. So the winner is 'mul' :)
You can run it on your browser by this link
https://jsperf.com/js-cast-str-to-number/1
I also tested var x = ~~"1000";. On Chrome and Safari, it is a little bit slower than var x = "1000"*1 (<1%), and on Firefox it is a little bit faster (<1%).
I use this way of converting string to number:
var str = "25"; // String
var number = str*1; // Number
So, when multiplying by 1, the value does not change, but JavaScript automatically returns a number.
But as it is shown below, this should be used if you are sure that the str is a number (or can be represented as a number), otherwise it will return NaN - not a number.
You can create simple function to use, e.g.,
function toNumber(str) {
return str*1;
}
Try parseInt.
var number = parseInt("10", 10); //number will have value of 10.
I love this trick:
~~"2.123"; //2
~~"5"; //5
The double bitwise negative drops off anything after the decimal point AND converts it to a number format. I've been told it's slightly faster than calling functions and whatnot, but I'm not entirely convinced.
Another method I just saw here (a question about the JavaScript >>> operator, which is a zero-fill right shift) which shows that shifting a number by 0 with this operator converts the number to a uint32 which is nice if you also want it unsigned. Again, this converts to an unsigned integer, which can lead to strange behaviors if you use a signed number.
"-2.123" >>> 0; // 4294967294
"2.123" >>> 0; // 2
"-5" >>> 0; // 4294967291
"5" >>> 0; // 5
In JavaScript, you can do the following:
ParseInt
parseInt("10.5") // Returns 10
Multiplying with 1
var s = "10";
s = s*1; // Returns 10
Using the unary operator (+)
var s = "10";
s = +s; // Returns 10
Using a bitwise operator
(Note: It starts to break after 2140000000. Example: ~~"2150000000" = -2144967296)
var s = "10.5";
s = ~~s; // Returns 10
Using Math.floor() or Math.ceil()
var s = "10";
s = Math.floor(s) || Math.ceil(s); // Returns 10
Please see the below example. It will help answer your question.
Example Result
parseInt("4") 4
parseInt("5aaa") 5
parseInt("4.33333") 4
parseInt("aaa"); NaN (means "Not a Number")
By using parseint function, it will only give op of integer present and not the string.
Beware if you use parseInt to convert a float in scientific notation!
For example:
parseInt("5.6e-14")
will result in
5
instead of
0
Also as a side note: MooTools has the function toInt() which is used on any native string (or float (or integer)).
"2".toInt() // 2
"2px".toInt() // 2
2.toInt() // 2
We can use +(stringOfNumber) instead of using parseInt(stringOfNumber).
Example: +("21") returns int of 21, like the parseInt("21").
We can use this unary "+" operator for parsing float too...
To convert a String into Integer, I recommend using parseFloat and not parseInt. Here's why:
Using parseFloat:
parseFloat('2.34cms') //Output: 2.34
parseFloat('12.5') //Output: 12.5
parseFloat('012.3') //Output: 12.3
Using parseInt:
parseInt('2.34cms') //Output: 2
parseInt('12.5') //Output: 12
parseInt('012.3') //Output: 12
So if you have noticed parseInt discards the values after the decimals, whereas parseFloat lets you work with floating point numbers and hence more suitable if you want to retain the values after decimals. Use parseInt if and only if you are sure that you want the integer value.
There are many ways in JavaScript to convert a string to a number value... All are simple and handy. Choose the way which one works for you:
var num = Number("999.5"); //999.5
var num = parseInt("999.5", 10); //999
var num = parseFloat("999.5"); //999.5
var num = +"999.5"; //999.5
Also, any Math operation converts them to number, for example...
var num = "999.5" / 1; //999.5
var num = "999.5" * 1; //999.5
var num = "999.5" - 1 + 1; //999.5
var num = "999.5" - 0; //999.5
var num = Math.floor("999.5"); //999
var num = ~~"999.5"; //999
My prefer way is using + sign, which is the elegant way to convert a string to number in JavaScript.
Try str - 0 to convert string to number.
> str = '0'
> str - 0
0
> str = '123'
> str - 0
123
> str = '-12'
> str - 0
-12
> str = 'asdf'
> str - 0
NaN
> str = '12.34'
> str - 0
12.34
Here are two links to compare the performance of several ways to convert string to int
https://jsperf.com/number-vs-parseint-vs-plus
http://phrogz.net/js/string_to_number.html
Here is the easiest solution
let myNumber = "123" | 0;
More easy solution
let myNumber = +"123";
In my opinion, no answer covers all edge cases as parsing a float should result in an error.
function parseInteger(value) {
if(value === '') return NaN;
const number = Number(value);
return Number.isInteger(number) ? number : NaN;
}
parseInteger("4") // 4
parseInteger("5aaa") // NaN
parseInteger("4.33333") // NaN
parseInteger("aaa"); // NaN
The easiest way would be to use + like this
const strTen = "10"
const numTen = +strTen // string to number conversion
console.log(typeof strTen) // string
console.log(typeof numTen) // number
I actually needed to "save" a string as an integer, for a binding between C and JavaScript, so I convert the string into an integer value:
/*
Examples:
int2str( str2int("test") ) == "test" // true
int2str( str2int("t€st") ) // "t¬st", because "€".charCodeAt(0) is 8364, will be AND'ed with 0xff
Limitations:
maximum 4 characters, so it fits into an integer
*/
function str2int(the_str) {
var ret = 0;
var len = the_str.length;
if (len >= 1) ret += (the_str.charCodeAt(0) & 0xff) << 0;
if (len >= 2) ret += (the_str.charCodeAt(1) & 0xff) << 8;
if (len >= 3) ret += (the_str.charCodeAt(2) & 0xff) << 16;
if (len >= 4) ret += (the_str.charCodeAt(3) & 0xff) << 24;
return ret;
}
function int2str(the_int) {
var tmp = [
(the_int & 0x000000ff) >> 0,
(the_int & 0x0000ff00) >> 8,
(the_int & 0x00ff0000) >> 16,
(the_int & 0xff000000) >> 24
];
var ret = "";
for (var i=0; i<4; i++) {
if (tmp[i] == 0)
break;
ret += String.fromCharCode(tmp[i]);
}
return ret;
}
String to Number in JavaScript:
Unary + (most recommended)
+numStr is easy to use and has better performance compared with others
Supports both integers and decimals
console.log(+'123.45') // => 123.45
Some other options:
Parsing Strings:
parseInt(numStr) for integers
parseFloat(numStr) for both integers and decimals
console.log(parseInt('123.456')) // => 123
console.log(parseFloat('123')) // => 123
JavaScript Functions
Math functions like round(numStr), floor(numStr), ceil(numStr) for integers
Number(numStr) for both integers and decimals
console.log(Math.floor('123')) // => 123
console.log(Math.round('123.456')) // => 123
console.log(Math.ceil('123.454')) // => 124
console.log(Number('123.123')) // => 123.123
Unary Operators
All basic unary operators, +numStr, numStr-0, 1*numStr, numStr*1, and numStr/1
All support both integers and decimals
Be cautious about numStr+0. It returns a string.
console.log(+'123') // => 123
console.log('002'-0) // => 2
console.log(1*'5') // => 5
console.log('7.7'*1) // => 7.7
console.log(3.3/1) // =>3.3
console.log('123.123'+0, typeof ('123.123' + 0)) // => 123.1230 string
Bitwise Operators
Two tilde ~~numStr or left shift 0, numStr<<0
Supports only integers, but not decimals
console.log(~~'123') // => 123
console.log('0123'<<0) // => 123
console.log(~~'123.123') // => 123
console.log('123.123'<<0) // => 123
// Parsing
console.log(parseInt('123.456')) // => 123
console.log(parseFloat('123')) // => 123
// Function
console.log(Math.floor('123')) // => 123
console.log(Math.round('123.456')) // => 123
console.log(Math.ceil('123.454')) // => 124
console.log(Number('123.123')) // => 123.123
// Unary
console.log(+'123') // => 123
console.log('002'-0) // => 2
console.log(1*'5') // => 5
console.log('7.7'*1) // => 7.7
console.log(3.3/1) // => 3.3
console.log('123.123'+0, typeof ('123.123'+0)) // => 123.1230 string
// Bitwise
console.log(~~'123') // => 123
console.log('0123'<<0) // => 123
console.log(~~'123.123') // => 123
console.log('123.123'<<0) // => 123
function parseIntSmarter(str) {
// ParseInt is bad because it returns 22 for "22thisendsintext"
// Number() is returns NaN if it ends in non-numbers, but it returns 0 for empty or whitespace strings.
return isNaN(Number(str)) ? NaN : parseInt(str, 10);
}
You can use plus.
For example:
var personAge = '24';
var personAge1 = (+personAge)
then you can see the new variable's type bytypeof personAge1 ; which is number.
Summing the multiplication of digits with their respective power of ten:
i.e: 123 = 100+20+3 = 1100 + 2+10 + 31 = 1*(10^2) + 2*(10^1) + 3*(10^0)
function atoi(array) {
// Use exp as (length - i), other option would be
// to reverse the array.
// Multiply a[i] * 10^(exp) and sum
let sum = 0;
for (let i = 0; i < array.length; i++) {
let exp = array.length - (i+1);
let value = array[i] * Math.pow(10, exp);
sum += value;
}
return sum;
}
The safest way to ensure you get a valid integer:
let integer = (parseInt(value, 10) || 0);
Examples:
// Example 1 - Invalid value:
let value = null;
let integer = (parseInt(value, 10) || 0);
// => integer = 0
// Example 2 - Valid value:
let value = "1230.42";
let integer = (parseInt(value, 10) || 0);
// => integer = 1230
// Example 3 - Invalid value:
let value = () => { return 412 };
let integer = (parseInt(value, 10) || 0);
// => integer = 0
Another option is to double XOR the value with itself:
var i = 12.34;
console.log('i = ' + i);
console.log('i ⊕ i ⊕ i = ' + (i ^ i ^ i));
This will output:
i = 12.34
i ⊕ i ⊕ i = 12
I only added one plus(+) before string and that was solution!
+"052254" // 52254
Number()
Number(" 200.12 ") // Returns 200.12
Number("200.12") // Returns 200.12
Number("200") // Returns 200
parseInt()
parseInt(" 200.12 ") // Return 200
parseInt("200.12") // Return 200
parseInt("200") // Return 200
parseInt("Text information") // Returns NaN
parseFloat()
It will return the first number
parseFloat("200 400") // Returns 200
parseFloat("200") // Returns 200
parseFloat("Text information") // Returns NaN
parseFloat("200.10") // Return 200.10
Math.floor()
Round a number to the nearest integer
Math.floor(" 200.12 ") // Return 200
Math.floor("200.12") // Return 200
Math.floor("200") // Return 200
function doSth(){
var a = document.getElementById('input').value;
document.getElementById('number').innerHTML = toNumber(a) + 1;
}
function toNumber(str){
return +str;
}
<input id="input" type="text">
<input onclick="doSth()" type="submit">
<span id="number"></span>
This (probably) isn't the best solution for parsing an integer, but if you need to "extract" one, for example:
"1a2b3c" === 123
"198some text2hello world!30" === 198230
// ...
this would work (only for integers):
var str = '3a9b0c3d2e9f8g'
function extractInteger(str) {
var result = 0;
var factor = 1
for (var i = str.length; i > 0; i--) {
if (!isNaN(str[i - 1])) {
result += parseInt(str[i - 1]) * factor
factor *= 10
}
}
return result
}
console.log(extractInteger(str))
Of course, this would also work for parsing an integer, but would be slower than other methods.
You could also parse integers with this method and return NaN if the string isn't a number, but I don't see why you'd want to since this relies on parseInt internally and parseInt is probably faster.
var str = '3a9b0c3d2e9f8g'
function extractInteger(str) {
var result = 0;
var factor = 1
for (var i = str.length; i > 0; i--) {
if (isNaN(str[i - 1])) return NaN
result += parseInt(str[i - 1]) * factor
factor *= 10
}
return result
}
console.log(extractInteger(str))
i need to replicate in Nodejs the results of the 3DS CBC encrypt in http://tripledes.online-domain-tools.com/.
This is my code:
const crypto = require('crypto');
const cipher = crypto.createCipher('des-ede3-cbc', key);
password = Buffer.from('MYPASS', 'utf8');
let encrypted = [cipher.update(password)];
encrypted.push(cipher.final());
encrypted = Buffer.concat(encryptedArr);
console.log(encrypted.toString('hex'));
The result of tripledes.online-domain-tools.com is:
Note that the result should be 59 30 20 02 a5 8c dd 5e, but my code gives me 33 97 d8 b0 e3 00 d1 53.
What am i missing?
Edit2:
Following your suggestions, I changed my code (Also added some Tests made with the guide of the NIST Publication):
const crypto = require('crypto');
function encrypt (inputkey, keyformat, password, passwordformat) {
let shortkey = Buffer.from(inputkey, keyformat);
let key = Buffer.alloc(24);
key.fill('\0');
for (i = 0; i < shortkey.length; i++) {
key[i] = shortkey[i];
}
let IV = Buffer.alloc(8);
const cipher = crypto.createCipheriv('des-ede3-cbc', key, IV);
password = Buffer.from(password, passwordformat);
let encryptedArr = [cipher.update(password)];
encryptedArr.push(cipher.final());
encrypted = Buffer.concat(encryptedArr);
return encrypted;
}
console.log(encrypt('1046913489980131','hex','0000000000000000','hex')); // works
console.log(encrypt('1007103489988020','hex','0000000000000000','hex')); // works
console.log(encrypt('10071034C8980120','hex','0000000000000000','hex')); // works
console.log(encrypt('1046103489988020','hex','0000000000000000','hex')); // works
console.log(encrypt('MYKEY','utf8','MYPASS','utf8')); // fails
Every Permutation Operation Known Answer Test of the NIST works great, but several other examples (including the one of the image) just fails
The reason i'm testing with this shady page is because my service provider is using it as reference.
This site made me some troubles for some time , well here is the implementation it uses internally to expand the key to be a 24 bytes !
i am going to talk about tripledes but i guess this would apply to other algorithms used by this site
step 1
it first checks if the key entered has the length that it expects it to be, (you can find a table at the bottom of that site telling the length of key for each Encryption algorithm)
if it does not it will complete with 0x00 bytes like this:
var key;// is a string containing the bytes wich will be used to encrypt the msg
var nullByte = 0x00;
var padding_needed;
for (var i=key.length ;i < expected_key_length ; ++)
{padding_needed =padding_needed + nullBute.tostring(16); }
key = key + padding_needed
so for example the length that it expects for 3DES is 24 bytes ; if you happen to enter just 15 bytes like this (112233445566778899aabbccddeeff) it will be like if you entered (112233445566778899aabbccddeeff00)
step2
in the case of tripledes the algorithm to expand the 16 bytes to 24 bytes key (which is the key length required by the algorithm) this site has a simple approach to do that
it copies the first 8 bytes and append it to the end of the key like this
key =key + key.substring(0,8);
and that is the key that is going to be given to the 3DES encryption function to work with
this simple approache is not used by openssl for example , open ssl uses the first 8 bytes of the MD5 of the key ,and append them to the 16 bytes of the original key to get the 24 bytes key that is required by 3DES, like this
key = key + (MD5(key)).substring(0,8);
Summary
in that tool if you enter the key 112233445566778899AABBCCDDEEFF is the same as if you entered 112233445566778899AABBCCDDEEFF00 and same as if you entered 112233445566778899AABBCCDDEEFF001122334455667788 so to solve your problem you should give your function the complete 24 bytes of key that you gave to that site and you will surely get the same results, beacause nodejs is probably is doing the same thing as openssl does to expand the key(uses md5)
PS
if you are using the cbc mode which is your case try to specify the IV to be 8 bytes of \x00 like this "0000000000000000"
the results will be the same !!
here is a working implementation of your code you can check it in the site
const crypto = require('crypto');
function encrypt (inputkey, keyformat, password, passwordformat) {
let shortkey = Buffer.from(inputkey, keyformat);
let key = Buffer.alloc(24);
key.fill('\0');
for (i = 0; i < shortkey.length; i++) {
key[i] = shortkey[i];
}
let IV = Buffer.alloc(8);
var expansionStart = shortkey.length>16?shortkey.length:16;
for (i=expansionStart;i<24;i++){
key[i]=key[i-expansionStart];
}
console.log(key);
const cipher = crypto.createCipheriv('des-ede3-cbc', key, IV);
password = Buffer.from(password, passwordformat);
let encryptedArr = [cipher.update(password)];
encryptedArr.push(cipher.final());
encrypted = Buffer.concat(encryptedArr);
return encrypted;
}
var enc = encrypt("112233445566778899AABBCCDDEEFF","hex","password","utf8");
console.log(enc);
I found a script that converts binary to string but how can I input a string and get the binary representation? so say I put in "P" I want it to output 01010000 as a string.
I have this but it is not what I am trying to do - it converts a string containing a binary number into a real value of that number:
///string_to_binary(string)
var str = argument0;
var output = "";
for(var i = 0; i < string_length(str); i++){
if(string_char_at(str, i + 1) == "0"){
output += "0";
}
else{
output += "1";
}
}
return real(output);
Tip: search for GML or other language term, these questions answered many times. Also please check your tag as it is the IDE tag, not language tag.
Im not familiar with GML myself, but a quick search showed this:
At least semi-official method for exactly this: http://www.gmlscripts.com/script/bytes_to_bin
/// bytes_to_bin(str)
//
// Returns a string of binary digits, 1 bit each.
//
// str raw bytes, 8 bits each, string
//
/// GMLscripts.com/license
{
var str, bin, p, byte;
str = argument0;
bin = "";
p = string_length(str);
repeat (p) {
byte = ord(string_char_at(str,p));
repeat (8) {
if (byte & 1) bin = "1" + bin else bin = "0" + bin;
byte = byte >> 1;
}
p -= 1;
}
return bin;
}
GML forum (has several examples) https://www.reddit.com/r/gamemaker/comments/4opzhu/how_could_i_convert_a_string_to_binary/
///string_to_binary(string)
var str = argument0;
var output = "";
for(var i = 0; i < string_length(str); i++){
if(string_char_at(str, i + 1) == "0"){
output += "0";
}
else{
output += "1";
}
}
return real(output);
And other language examples:
C++ Fastest way to Convert String to Binary?
#include <string>
#include <bitset>
#include <iostream>
using namespace std;
int main(){
string myString = "Hello World";
for (std::size_t i = 0; i < myString.size(); ++i)
{
cout << bitset<8>(myString.c_str()[i]) << endl;
}
}
Java: Convert A String (like testing123) To Binary In Java
String s = "foo";
byte[] bytes = s.getBytes();
StringBuilder binary = new StringBuilder();
for (byte b : bytes)
{
int val = b;
for (int i = 0; i < 8; i++)
{
binary.append((val & 128) == 0 ? 0 : 1);
val <<= 1;
}
binary.append(' ');
}
System.out.println("'" + s + "' to binary: " + binary);
JS: How to convert text to binary code in JavaScript?
function convert() {
var output = document.getElementById("ti2");
var input = document.getElementById("ti1").value;
output.value = "";
for (var i = 0; i < input.length; i++) {
output.value += input[i].charCodeAt(0).toString(2) + " ";
}
}
I was looking around for a simple GML script to convert a decimal to binary and return the bits in an array. I didn't find anything for my need and to my liking so I rolled my own. Short and sweet.
The first param is the decimal number (string or decimal) and the second param is the bit length.
// dec_to_bin(num, len);
// argument0, decimal string
// argument1, integer
var num = real(argument0);
var len = argument1;
var bin = array_create(len, 0);
for (var i = len - 1; i >= 0; --i) {
bin[i] = floor(num % 2);
num -= num / 2;
}
return bin;
Usage:
dec_to_bin("48", 10);
Output:
{ { 0,0,0,0,1,1,0,0,0,0 }, }
i think the binary you mean is the one that computers use, if thats the case, just use the common binary and add a kind of identification.
binary is actually simple, instead of what most people think.
every digit represents the previous number *2 (2¹, 2², 2³...) so we get:
1, 2, 4, 8, 16, 32, 64, 128, 256, 512...
flip it and get:
...512, 256, 128, 64, 32, 16, 8, 4, 2, 1
every digit is "activated" with 1's, plus all the activated number ant thats the value.
ok, so binary is basically another number system, its not like codes or something. Then how are letters and other characters calculated?
they arent ;-;
we just represent then as their order on their alphabets, so:
a=1
b=2
c=3
...
this means that "b" in binary would be "10", but "2" is also "10". So thats where computer's binary enter.
they just add a identification before the actual number, so:
letter_10 = b
number_10 = 2
signal_10 = "
wait, but if thats binary there cant be letter on it, instead another 0's and 1's are used, so:
011_10 = b
0011_10 = 2
001_10 = "
computers also cant know where the number starts and ends, so you have to always use the same amount of numbers, which is 8. now we get:
011_00010 = b
0011_0010 = 2
001_00010 = "
then remove the "_" cuz again, computers will only use 0's and 1's. and done!
so what i mean is, just use the code you had and add 00110000 to the value, or if you want to translate these numbers to letters as i wanted just add 01100000
in that case where you have the letter and wants the binary, first convert the letter to its number, for it just knows that the letters dont start at 1, capitalized letters starts at 64 and the the non-capitalized at 96.
ord("p")=112
112-96=16
16 in binary is 10000
10000 + 01100000 = 01110000
"p" in binary is 01110000
ord("P")=80
80-64=16
16 in binary is 10000
10000 + 01000000 = 01010000
"P" in binary is 01010000
thats just a explanation of what the code should do, actually im looking for a simple way to turn binary cuz i cant understand much of the code you showed.
(011)
1000 1111 10000 101 1001 1000 101 1100 10000 101 100
I have to generate unique URL part which will be "unguessable" and "resistant" to brute force attack. It also has to be as short as possible :) and all generated values has to be of same length. I was thinking about using UUID V4 which can be represented by 32 (without hyphens) hex chars de305d5475b4431badb2eb6b9e546014 but it's a bit too long. So my question is how to generate something unqiue, that can be represented with url charcters with same length for each generated value and shorter than 32 chars. (In node.js or pgpsql)
v4() will generate a large number which is translated into a hexadecimal string. In Node.js you can use Buffer to convert the string into a smaller base64 encoding:
import { v4 } from 'uuid';
function getRandomName() {
let hexString = v4();
console.log("hex: ", hexString);
// remove decoration
hexString = hexString.replace(/-/g, "");
let base64String = Buffer.from(hexString, 'hex').toString('base64')
console.log("base64:", base64String);
return base64String;
}
Which produces:
hex: 6fa1ca99-a92b-4d2a-aac2-7c7977119ebc
base64: b6HKmakr
hex: bd23c8fd-0f62-49f4-9e51-8b5c97601a16
base64: vSPI/Q9i
UUID v4 itself does not actually guarantee uniqueness. It's just very, very unlikely that two randomly generated UUIDs will clash. That's why they need to be so long - that reduces the clashing chance.
So you can make it shorter, but the shorter you make it, the more likely that it won't actually be unique. UUID v4 is 128 bit long because that is commonly considered "unique enough".
The short-uuid module does just that.
"Generate and translate standard UUIDs into shorter - or just different - formats and back."
It accepts custom character sets (and offers a few) to translate the UUID to and fro.
You can also base64 the uuid which shortens it a bit to 22. Here's a playground.
It all depends on how guessable/unique it has to be.
My suggestion would be to generate 128 random bits and then encode it using base36. That would give you a "nice" URL and it would be unique and probably unguessable enough.
If you want it even shorter you can use base64, but base64 needs to contain two non alphanumeric characters.
This is a fairly old thread, but I'd like to point out the top answer does not produce the results it claims. It will actually produce strings that are ~32 characters long, but the examples claim 8 characters. If you want more compression convert the uuid to base 90 using this function.
Using Base64 takes 4 characters for every 3 bytes, and Hex (Base16) takes 2 characters for each byte. This means that Base64 will have ~67% better storage size than hex, but if we can increase that character/byte ratio we can get even better compression. Base90 gives ever so slightly more compression because of this.
const hex = "0123456789abcdef";
const base90 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!#$%&'()*+-./:<=>?#[]^_`{|}~";
/**
* Convers a Base16 (Hex) represented string to a Base 90 String.
* #param {String} number Hex represented string
* #returns A Base90 representation of the hex string
*/
function convertToBase90(number) {
var i,
divide,
newlen,
numberMap = {},
fromBase = hex.length,
toBase = base90.length,
length = number.length,
result = typeof number === "string" ? "" : [];
for (i = 0; i < length; i++) {
numberMap[i] = hex.indexOf(number[i]);
}
do {
divide = 0;
newlen = 0;
for (i = 0; i < length; i++) {
divide = divide * fromBase + numberMap[i];
if (divide >= toBase) {
numberMap[newlen++] = parseInt(divide / toBase, 10);
divide = divide % toBase;
} else if (newlen > 0) {
numberMap[newlen++] = 0;
}
}
length = newlen;
result = base90.slice(divide, divide + 1).concat(result);
} while (newlen !== 0);
return result;
}
/**
* Compresses a UUID String to base 90 resulting in a shorter UUID String
* #param {String} uuid The UUID string to compress
* #returns A compressed UUID String.
*/
function compressUUID(uuid) {
uuid = uuid.replace(/-/g, "");
return convertToBase90(uuid);
}
Over a few million random uuids this generates no duplicates and the following output:
Lengths:
Avg: 19.959995 Max: 20 Min: 17
Examples:
Hex: 68f75ee7-deb6-4c5c-b315-3cc6bd7ca0fd
Base 90: atP!.AcGJh1(eW]1LfAh
Hex: 91fb8316-f033-40d1-974d-20751b831c4e
Base 90: ew-}Kv&nK?y#~xip5/0e
Hex: 4cb167ee-eb4b-4a76-90f2-6ced439d5ca5
Base 90: 7Ng]V/:0$PeS-K?!uTed
UUID is 36 characters long and you can shorten it to 22 characters (~30%) if you want save ability to convert it back and for it to be url safe.
Here is pure node solution for base64 url safe string:
type UUID = string;
type Base64UUID = string;
/**
* Convert uuid to base64url
*
* #example in: `f32a91da-c799-4e13-aa17-8c4d9e0323c9` out: `8yqR2seZThOqF4xNngMjyQ`
*/
export function uuidToBase64(uuid: UUID): Base64UUID {
return Buffer.from(uuid.replace(/-/g, ''), 'hex').toString('base64url');
}
/**
* Convert base64url to uuid
*
* #example in: `8yqR2seZThOqF4xNngMjyQ` out: `f32a91da-c799-4e13-aa17-8c4d9e0323c9`
*/
export function base64toUUID(base64: Base64UUID): UUID {
const hex = Buffer.from(base64, 'base64url').toString('hex');
return `${hex.substring(0, 8)}-${hex.substring(8, 12)}-${hex.substring(
12,
16,
)}-${hex.substring(16, 20)}-${hex.substring(20)}`;
}
Test:
import { randomUUID } from "crypto";
// f32a91da-c799-4e13-aa17-8c4d9e0323c9
const uuid = randomUUID();
// 8yqR2seZThOqF4xNngMjyQ
const base64 = uuidToBase64(uuid);
// f32a91da-c799-4e13-aa17-8c4d9e0323c9
const uuidFromBase64 = base64toUUID(base64);