I have a string called e3 which holds the string 1,2,4,5,3,6. I want to add up all of those numbers up to make the number 21 I was considering doing a for loop for this however I do not know how to turn part of a string into its own value.
I anyone has any better idea of what to do please comment, or answer.
You could use String#split for the string and use Array#reduce for summing.
var e3 = '1,2,4,5,3,6',
sum = e3.split(',').reduce(function (a, b) {
return a + +b; // +b forces b to number
}, 0);
console.log(sum);
If you are sure that it is always a comma separated list of numbers, you could split it on the comma into an array and then use array.reduce() to sum them
var asString = '1,2,4,5,3,6';
var asArray = asString.split(',');
var total = asArray.reduce(function(prev, current){
return prev + parseInt(current, 10);
}, 0);
console.log(total) // outputs 21;
You can do it like this:
var e3 = "1,2,4,5,3,6";
// Split by separator ','
var stringsArr = e3.split(',');
var sum = 0;
// Loop through array of string numbers
stringsArr.forEach(function(str) {
// get Int from a string
var strVal = parseInt(str, 10);
sum += strVal;
});
here's the fiddle
Here is working code to do what you need: https://plnkr.co/edit/8LSkZi0oC8msbHI0qOrz?p=preview
At first you use the split method - this separates a string into an array of strings, based on some separator value. In our case, the separator is a comma, but it could be a blank space or something else:
var testString = '1,2,4,5,3,6';
var separator = ',';
function splitStringOnCommasAndGetArray(string, separator){
var arrayOfStrings = string.split(separator);
return arrayOfStrings;
}
After that, we loop through the array and turn each value into a number. We add the numbers, like so:
function addUpArray(arrayOfStrings){
var totalNumber = 0;
for(var i = 0; i < arrayOfStrings.length; i++){
var currentNum = parseInt(arrayOfStrings[i]);
console.log(currentNum);
totalNumber += currentNum;
}
return totalNumber;
}
Related
I have a string with diffrent mathematical characters, and i want to make the last number negative/positive. Let's say the string is "100/5*30-60+333". The result i want is "100/5*30-60+(-333)", and i want to convert it back to positive ("100/5*30-60+333").
function posNeg() {
// hiddenText is a <input> element. This is not shown.
let n = hiddenText.value;
n.split('+');
n.split('-');
n.split('*');
n.split('/');
console.log(n);
}
What i get is the whole hiddenText.value, and not an array of all numbers. Any tips?
First, I'd match all of the basic math operators to get their order:
const operatorsArr = n.match(/\+|\-|\/|\*/g)
Then, split the string:
function posNeg() {
// hiddenText is a <input> element. This is not shown.
let n = hiddenText.value;
n = n.replace(/\+|\-|\/|\*/g, '|');
n = n.split('|');
console.log(n);
}
Then, you will have an array of numbers, in which you can mutate the last number easily:
n[n.lengh-1] *= -1;
Now we can combine the two arrays together:
let newArr;
for (let i = 0; i < n.length; i++) {
newArr.push(n[i]);
if (operatorsArr[i]) newArr.push(operatorsArr[i]);
}
At last, you can rejoin the array to create the new String with a seperator of your choosing. In this example I'm using a space:
newArr = newArr.join(' ')
Please let me know how that works out for you.
Let's say the string is "100/5*30-60+333". The result i want is
"100/5*30-60+(-333)", and i want to convert it back to positive
("100/5*30-60+333").
The following code does that:
let mathStr = '100/5*30-60+333';
console.log(mathStr);
let tokens = mathStr.split('+');
let index = tokens.length - 1;
let lastToken = tokens[index];
lastToken = '('.concat('-', lastToken, ')');
let newMathStr = tokens[0].concat('+', lastToken);
console.log(newMathStr); // 100/5*30-60+(-333)
console.log(mathStr); // 100/5*30-60+333
EDIT:
... and i want to convert it back to positive ("100/5*30-60+333").
One way is to declare mathStr (with the value "100/5*30-60+333") as a var at the beginning and reuse it, later as you need. Another way is to code as follows:
let str = "100/5*30-60+(-333)";
str = str.replace('(-', '').replace(')', '');
console.log(str); // 100/5*30-60+333
To get numbers You can use replace function and split check code bellow :
function posNeg() {
// hiddenText is a <input> element. This is not shown.
let n = "100/5*30-60+333";
n = n.replace('+','|+');
n = n.replace('-','|-');
n = n.replace('*','|*');
n = n.replace('/','|/');
n=n.split('|');console.log(n);
// to use any caracter from array use it in removeop like example
// if we have array (split return) have 100 5 30 60 333 we get 100 for example
// we need to make removeop(n[0]) and that reutrn 100;
// ok now to replace last value to negative in string you can just make
// var lastv=n[n.length-1];
// n[n.length-1] ='(-'+n[n.length-1])+')';
//var newstring=n.join('');
//n[n.length-1]=lastv;
//var oldstring=n.join('');
}
function removeop(stringop)
{
stringop = stringop.replace('+','');
stringop = stringop.replace('-','');
stringop = stringop.replace('*','');
stringop = stringop.replace('/','');
return stringop;
}
If you really need to add "()", then you can modify accordingly
<script>
function myConversion(){
var str = "100/5*30-60-333";
var p = str.lastIndexOf("+");
if(p>-1)
{
str = str.replaceAt(p,"-");
}
else
{
var n = str.lastIndexOf("-");
if(n>-1)
str = str.replaceAt(n,"+");
}
console.log(str);
}
String.prototype.replaceAt=function(index, replacement) {
return this.substr(0, index) + replacement+ this.substr(index + replacement.length);
}
</script>
I created a function with a regular expression and then iterated over the array by adding the previous total to the next index in the array.
My code isn't working. Is my logic off? Ignore the syntax
function sumofArr(arr) { // here i create a function that has one argument called arr
var total = 0; // I initialize a variable and set it equal to 0
var str = "12sf0as9d" // this is the string where I want to add only integers
var patrn = \\D; // this is the regular expression that removes the letters
var tot = str.split(patrn) // here i add split the string and store it into an array with my pattern
arr.forEach(function(tot) { // I use a forEach loop to iterate over the array
total += tot; // add the previous total to the new total
}
return total; // return the total once finished
}
var patrn = \\D; // this is the regular expression that removes the letters
This is not a valid regular expression in JavaScript.
You are also missing a closing bracket in the end of your code.
A simpler solution would be to find all integers in the string, to convert them into numbers (e.g. using the + operator) and summing them up (e.g. using a reduce operation).
var str = "12sf0as9d";
var pattern = /\d+/g;
var total = str.match(pattern).reduce(function(prev, num) {
return prev + +num;
}, 0);
console.log(str.match(pattern)); // ["12", "0", "9"]
console.log(total); // 21
you have some errors :
change var patrn = \\D with var patrn = "\\D"
use parseInt : total += parseInt(tot);
function sumofArr(arr){ // here i create a function that has one argument called arr
var total = 0; // I initialize a variable and set it equal to 0
var str = "12sf0as9d" // this is the string where I want to add only integers
var patrn = "\\D"; // this is the regular expression that removes the letters
var tot = str.split(patrn) // here i add split the string and store it into an array with my pattern
arr.forEach(function(tot){ // I use a forEach loop to iterate over the array
total += parseInt(tot); // add the previous total to the new total
})
return total; // return the total once finished
}
alert(sumofArr(["1", "2", "3"]));
https://jsfiddle.net/efrow9zs/
function sumofArr(str) {
var tot = str.replace(/\D/g,'').split('');
return tot.reduce(function(prev, next) {
return parseInt(prev, 10) + parseInt(next, 10);
});}
sumofArr("12sf0as9d");
Alright so I'm trying to completely split a number into an Array. So for example:
var num = 55534;
var arr = []; <- I would want the Array to look like this [5,5,5,3,4]
Basically i want to to completely split the number apart and place each Number into its own element of the array. Usually in the past i would just convert the number into a string then use the .split() function. This is how i use to do it:
num += "";
var arr = num.split("");
But this time i actually need to use these numbers, so they can not be strings. What would you guys say be the way of doing this?
Update, after the edit for some reason my code is crashing every run:
function DashInsert(num) {
num += "";
var arr = num.split("").map(Number); // [9,9,9,4,6]
for(var i = 0; i < arr.length; i++){
if(arr[i] % 2 === 1){
arr.splice(i,0,"-");
}// odd
}
return arr.join("");
}
String(55534).split("").map(Number)
...will handily do your trick.
You can do what you already did, and map a number back:
55534..toString().split('').map(Number)
//^ [5,5,5,3,4]
I'll do it like bellow
var num = 55534;
var arr = num.toString().split(''); //convert string to number & split by ''
var digits = arr.map(function(el){return +el}) //convert each digit to numbers
console.log(digits); //prints [5, 5, 5, 3, 4]
Basically I'm converting each string into numbers, you can just pass Number function into map also.
Is there a possibility to wrap each character in Javascript and prepend zero's if its less then X digits?
What i get/have:
var votes = 2;
//or
var votes = 123;
//or
var votes = 4321;
what it should to look like:
<span>0</span><span>0</span><span>0</span><span>2</span>
//or
<span>0</span><span>1</span><span>2</span><span>3</span>
//or
<span>4</span><span>3</span><span>2</span><span>1</span>
so the result should be a number with four digits.
here's a tricky version:
var votes = 123;
("0000" + votes).slice(-4); /* 0123 */
thus, to wrap each digit in a <span> you could fetch each digit with $.map and wrap it into its own element, like in this example fiddle: http://jsfiddle.net/cZAWj/
var votes = 973;
$.map(("0000" + votes).slice(-4), function(digit) {
$('<span/>', { text : digit }).appendTo($('body'));
});
Firstly, make it look like a string and pad it...
function pad(number, length) {
var str = '' + number;
while (str.length < length) {
str = '0' + str;
}
return str;
}
Then you can iterate over it and add a span around each number. Then write the markup out as the .html of the parent element.
Well one way to do it would be to convert the number to a string and pre-append 0 until we reach the desired length.
So if you want X digits:
var strNb = "" + nb;
while (strNb.length < X){
strNb = "0" + strNb
}
function formatNumber(d, x) {
var l = String(d).length;
return (l<x?(Array(x-l).join('0') + d):String(d)).replace(/\d/g,"<span>$&</span>");
}
i want int from string in javascript how i can get them from
test1 , stsfdf233, fdfk323,
are anyone show me the method to get the integer from this string.
it is a rule that int is always in the back of the string.
how i can get the int who was at last in my string
var s = 'abc123';
var number = s.match(/\d+$/);
number = parseInt(number, 10);
The first step is a simple regular expression - \d+$ will match the digits near the end.
On the next step, we use parseInt on the string we've matched before, to get a proper number.
You can use a regex to extract the numbers in the string via String#match, and convert each of them to a number via parseInt:
var str, matches, index, num;
str = "test123and456";
matches = str.match(/\d+/g);
for (index = 0; index < matches.length; ++index) {
num = parseInt(matches[index], 10);
display("Digit series #" + index + " converts to " + num);
}
Live Example
If the numbers really occur only at the ends of the strings or you just want to convert the first set of digits you find, you can simplify a bit:
var str, matches, num;
str = "test123";
matches = str.match(/\d+/);
if (matches) {
num = parseInt(matches[0], 10);
display("Found match, converts to: " + num);
}
else {
display("No digits found");
}
Live example
If you want to ignore digits that aren't at the end, add $ to the end of the regex:
matches = str.match(/\d+$/);
Live example
var str = "stsfdf233";
var num = parseInt(str.replace(/\D/g, ''), 10);
var match = "stsfdf233".match(/\d+$/);
var result = 0; // default value
if(match != null) {
result = parseInt(match[0], 10);
}
Yet another alternative, this time without any replace or Regular Expression, just one simple loop:
function ExtractInteger(sValue)
{
var sDigits = "";
for (var i = sValue.length - 1; i >= 0; i--)
{
var c = sValue.charAt(i);
if (c < "0" || c > "9")
break;
sDigits = c + sDigits;
}
return (sDigits.length > 0) ? parseInt(sDigits, 10) : NaN;
}
Usage example:
var s = "stsfdf233";
var n = ExtractInteger(s);
alert(n);
This might help you
var str = 'abc123';
var number = str.match(/\d/g).join("");
Use my extension to String class :
String.prototype.toInt=function(){
return parseInt(this.replace(/\D/g, ''),10);
}
Then :
"ddfdsf121iu".toInt();
Will return an integer : 121
First positive or negative number:
"foo-22bar11".match(/-?\d+/); // -22
javascript:alert('stsfdf233'.match(/\d+$/)[0])
Global.parseInt with radix is overkill here, regexp extracted decimal digits already and rigth trimmed string