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Removing last two characters of a string [duplicate]

I have a string, 12345.00, and I would like it to return 12345.0.
I have looked at trim, but it looks like it is only trimming whitespace and slice which I don't see how this would work. Any suggestions?

You can use the substring function:
let str = "12345.00";
str = str.substring(0, str.length - 1);
console.log(str);
This is the accepted answer, but as per the conversations below, the slice syntax is much clearer:
let str = "12345.00";
str = str.slice(0, -1);
console.log(str);

You can use slice! You just have to make sure you know how to use it. Positive #s are relative to the beginning, negative numbers are relative to the end.
js>"12345.00".slice(0,-1)
12345.0

You can use the substring method of JavaScript string objects:
s = s.substring(0, s.length - 4)
It unconditionally removes the last four characters from string s.
However, if you want to conditionally remove the last four characters, only if they are exactly _bar:
var re = /_bar$/;
s.replace(re, "");

The easiest method is to use the slice method of the string, which allows negative positions (corresponding to offsets from the end of the string):
const s = "your string";
const withoutLastFourChars = s.slice(0, -4);
If you needed something more general to remove everything after (and including) the last underscore, you could do the following (so long as s is guaranteed to contain at least one underscore):
const s = "your_string";
const withoutLastChunk = s.slice(0, s.lastIndexOf("_"));
console.log(withoutLastChunk);

For a number like your example, I would recommend doing this over substring:
console.log(parseFloat('12345.00').toFixed(1));
Do note that this will actually round the number, though, which I would imagine is desired but maybe not:
console.log(parseFloat('12345.46').toFixed(1));

Be aware that String.prototype.{ split, slice, substr, substring } operate on UTF-16 encoded strings
None of the previous answers are Unicode-aware.
Strings are encoded as UTF-16 in most modern JavaScript engines, but higher Unicode code points require surrogate pairs, so older, pre-existing string methods operate on UTF-16 code units, not Unicode code points.
See: Do NOT use .split('').
const string = "ẞ🦊";
console.log(string.slice(0, -1)); // "ẞ\ud83e"
console.log(string.substr(0, string.length - 1)); // "ẞ\ud83e"
console.log(string.substring(0, string.length - 1)); // "ẞ\ud83e"
console.log(string.replace(/.$/, "")); // "ẞ\ud83e"
console.log(string.match(/(.*).$/)[1]); // "ẞ\ud83e"
const utf16Chars = string.split("");
utf16Chars.pop();
console.log(utf16Chars.join("")); // "ẞ\ud83e"
In addition, RegExp methods, as suggested in older answers, don’t match line breaks at the end:
const string = "Hello, world!\n";
console.log(string.replace(/.$/, "").endsWith("\n")); // true
console.log(string.match(/(.*).$/) === null); // true
Use the string iterator to iterate characters
Unicode-aware code utilizes the string’s iterator; see Array.from and ... spread.
string[Symbol.iterator] can be used (e.g. instead of string) as well.
Also see How to split Unicode string to characters in JavaScript.
Examples:
const string = "ẞ🦊";
console.log(Array.from(string).slice(0, -1).join("")); // "ẞ"
console.log([
...string
].slice(0, -1).join("")); // "ẞ"
Use the s and u flags on a RegExp
The dotAll or s flag makes . match line break characters, the unicode or u flag enables certain Unicode-related features.
Note that, when using the u flag, you eliminate unnecessary identity escapes, as these are invalid in a u regex, e.g. \[ is fine, as it would start a character class without the backslash, but \: isn’t, as it’s a : with or without the backslash, so you need to remove the backslash.
Examples:
const unicodeString = "ẞ🦊",
lineBreakString = "Hello, world!\n";
console.log(lineBreakString.replace(/.$/s, "").endsWith("\n")); // false
console.log(lineBreakString.match(/(.*).$/s) === null); // false
console.log(unicodeString.replace(/.$/su, "")); // ẞ
console.log(unicodeString.match(/(.*).$/su)[1]); // ẞ
// Now `split` can be made Unicode-aware:
const unicodeCharacterArray = unicodeString.split(/(?:)/su),
lineBreakCharacterArray = lineBreakString.split(/(?:)/su);
unicodeCharacterArray.pop();
lineBreakCharacterArray.pop();
console.log(unicodeCharacterArray.join("")); // "ẞ"
console.log(lineBreakCharacterArray.join("").endsWith("\n")); // false
Note that some graphemes consist of more than one code point, e.g. 🏳️‍🌈 which consists of the sequence 🏳 (U+1F3F3), VS16 (U+FE0F), ZWJ (U+200D), 🌈 (U+1F308).
Here, even Array.from will split this into four “characters”.
Matching those is made easier with the RegExp set notation and properties of strings proposal.

Using JavaScript's slice function:
let string = 'foo_bar';
string = string.slice(0, -4); // Slice off last four characters here
console.log(string);
This could be used to remove '_bar' at end of a string, of any length.

A regular expression is what you are looking for:
let str = "foo_bar";
console.log(str.replace(/_bar$/, ""));

Try this:
const myString = "Hello World!";
console.log(myString.slice(0, -1));

Performance
Today 2020.05.13 I perform tests of chosen solutions on Chrome v81.0, Safari v13.1 and Firefox v76.0 on MacOs High Sierra v10.13.6.
Conclusions
the slice(0,-1)(D) is fast or fastest solution for short and long strings and it is recommended as fast cross-browser solution
solutions based on substring (C) and substr(E) are fast
solutions based on regular expressions (A,B) are slow/medium fast
solutions B, F and G are slow for long strings
solution F is slowest for short strings, G is slowest for long strings
Details
I perform two tests for solutions A, B, C, D, E(ext), F, G(my)
for 8-char short string (from OP question) - you can run it HERE
for 1M long string - you can run it HERE
Solutions are presented in below snippet
function A(str) {
return str.replace(/.$/, '');
}
function B(str) {
return str.match(/(.*).$/)[1];
}
function C(str) {
return str.substring(0, str.length - 1);
}
function D(str) {
return str.slice(0, -1);
}
function E(str) {
return str.substr(0, str.length - 1);
}
function F(str) {
let s= str.split("");
s.pop();
return s.join("");
}
function G(str) {
let s='';
for(let i=0; i<str.length-1; i++) s+=str[i];
return s;
}
// ---------
// TEST
// ---------
let log = (f)=>console.log(`${f.name}: ${f("12345.00")}`);
[A,B,C,D,E,F,G].map(f=>log(f));
This snippet only presents soutions
Here are example results for Chrome for short string

Use regex:
let aStr = "12345.00";
aStr = aStr.replace(/.$/, '');
console.log(aStr);

How about:
let myString = "12345.00";
console.log(myString.substring(0, myString.length - 1));

1. (.*), captures any character multiple times:
console.log("a string".match(/(.*).$/)[1]);
2. ., matches last character, in this case:
console.log("a string".match(/(.*).$/));
3. $, matches the end of the string:
console.log("a string".match(/(.*).{2}$/)[1]);

https://stackoverflow.com/questions/34817546/javascript-how-to-delete-last-two-characters-in-a-string
Just use trim if you don't want spaces
"11.01 °C".slice(0,-2).trim()

Here is an alternative that i don't think i've seen in the other answers, just for fun.
var strArr = "hello i'm a string".split("");
strArr.pop();
document.write(strArr.join(""));
Not as legible or simple as slice or substring but does allow you to play with the string using some nice array methods, so worth knowing.

debris = string.split("_") //explode string into array of strings indexed by "_"
debris.pop(); //pop last element off the array (which you didn't want)
result = debris.join("_"); //fuse the remainng items together like the sun

If you want to do generic rounding of floats, instead of just trimming the last character:
var float1 = 12345.00,
float2 = 12345.4567,
float3 = 12345.982;
var MoreMath = {
/**
* Rounds a value to the specified number of decimals
* #param float value The value to be rounded
* #param int nrDecimals The number of decimals to round value to
* #return float value rounded to nrDecimals decimals
*/
round: function (value, nrDecimals) {
var x = nrDecimals > 0 ? 10 * parseInt(nrDecimals, 10) : 1;
return Math.round(value * x) / x;
}
}
MoreMath.round(float1, 1) => 12345.0
MoreMath.round(float2, 1) => 12345.5
MoreMath.round(float3, 1) => 12346.0
EDIT: Seems like there exists a built in function for this, as Paolo points out. That solution is obviously much cleaner than mine. Use parseFloat followed by toFixed

if(str.substring(str.length - 4) == "_bar")
{
str = str.substring(0, str.length - 4);
}

Via slice(indexStart, indexEnd) method - note, this does NOT CHANGE the existing string, it creates a copy and changes the copy.
console.clear();
let str = "12345.00";
let a = str.slice(0, str.length -1)
console.log(a, "<= a");
console.log(str, "<= str is NOT changed");
Via Regular Expression method - note, this does NOT CHANGE the existing string, it creates a copy and changes the copy.
console.clear();
let regExp = /.$/g
let b = str.replace(regExp,"")
console.log(b, "<= b");
console.log(str, "<= str is NOT changed");
Via array.splice() method -> this only works on arrays, and it CHANGES, the existing array (so careful with this one), you'll need to convert a string to an array first, then back.
console.clear();
let str = "12345.00";
let strToArray = str.split("")
console.log(strToArray, "<= strToArray");
let spliceMethod = strToArray.splice(str.length-1, 1)
str = strToArray.join("")
console.log(str, "<= str is changed now");

In cases where you want to remove something that is close to the end of a string (in case of variable sized strings) you can combine slice() and substr().
I had a string with markup, dynamically built, with a list of anchor tags separated by comma. The string was something like:
var str = "<a>text 1,</a><a>text 2,</a><a>text 2.3,</a><a>text abc,</a>";
To remove the last comma I did the following:
str = str.slice(0, -5) + str.substr(-4);

You can, in fact, remove the last arr.length - 2 items of an array using arr.length = 2, which if the array length was 5, would remove the last 3 items.
Sadly, this does not work for strings, but we can use split() to split the string, and then join() to join the string after we've made any modifications.
var str = 'string'
String.prototype.removeLast = function(n) {
var string = this.split('')
string.length = string.length - n
return string.join('')
}
console.log(str.removeLast(3))

Try to use toFixed
const str = "12345.00";
return (+str).toFixed(1);

Try this:
<script>
var x="foo_foo_foo_bar";
for (var i=0; i<=x.length; i++) {
if (x[i]=="_" && x[i+1]=="b") {
break;
}
else {
document.write(x[i]);
}
}
</script>
You can also try the live working example on http://jsfiddle.net/informativejavascript/F7WTn/87/.

#Jason S:
You can use slice! You just have to
make sure you know how to use it.
Positive #s are relative to the
beginning, negative numbers are
relative to the end.
js>"12345.00".slice(0,-1)
12345.0
Sorry for my graphomany but post was tagged 'jquery' earlier. So, you can't use slice() inside jQuery because slice() is jQuery method for operations with DOM elements, not substrings ...
In other words answer #Jon Erickson suggest really perfect solution.
However, your method will works out of jQuery function, inside simple Javascript.
Need to say due to last discussion in comments, that jQuery is very much more often renewable extension of JS than his own parent most known ECMAScript.
Here also exist two methods:
as our:
string.substring(from,to) as plus if 'to' index nulled returns the rest of string. so:
string.substring(from) positive or negative ...
and some other - substr() - which provide range of substring and 'length' can be positive only:
string.substr(start,length)
Also some maintainers suggest that last method string.substr(start,length) do not works or work with error for MSIE.

Use substring to get everything to the left of _bar. But first you have to get the instr of _bar in the string:
str.substring(3, 7);
3 is that start and 7 is the length.

Regex expression to get numbers without parentheses ()

I'm trying to create a regex that will select the numbers/numbers with commas(if easier, can trim commas later) that do not have a parentheses after and not the numbers inside the parentheses should not be selected either.
Used with the JavaScript's String.match method
Example strings
9(296,178),5,3(123),10
10,9(296,178),2,5,3(123),3(124,125)
10,7,5(296,293,444,1255),3(218),2,4
What i have so far:
/((^\d+[^\(])|(,\d+,)|(,*\d+$))/gm
I tried this in regex101 and underlined the numbers i would like to match and x on the one that should not.

You could start with a substitution to remove all the unwanted parts:
/\d*\(.*?\),?//gm
Demo
This leaves you with
5,10
10,2,5,
10,7,2,4
which makes the matching pretty straight forward:
/(\d+)/gm
If you want it as a single match expression you could use a negative lookbehind:
/(?<!\([\d,]*)(\d+)(?:,|$)/gm
Demo - and here's the same matching expression as a runnable javascript (skeleton code borrowed from Wiktor's answer):
const text = `9(296,178),5,3(123),10
10,9(296,178),2,5,3(123),3(124,125)
10,7,5(296,293,444,1255),3(218),2,4`;
const matches = Array.from(text.matchAll(/(?<!\([\d,]*)(\d+)(?:,|$)/gm), x=>x[1])
console.log(matches);

Here, I'd recommend the so-called "best regex trick ever": just match what you do not need (negative contexts) and then match and capture what you need, and grab the captured items only.
If you want to match integer numbers that are not matched with \d+\([^()]*\) pattern (a number followed with a parenthetical substring), you can match this pattern or match and capture the \d+, one or more digit matching pattern, and then simply grab Group 1 values from matches:
const text = `9(296,178),5,3(123),10
10,9(296,178),2,5,3(123),3(124,125)
10,7,5(296,293,444,1255),3(218),2,4`;
const matches = Array.from(text.matchAll(/\d+\([^()]*\)|(\d+)/g), x=> x[1] ?? "").filter(Boolean)
console.log(matches);
Details:
text.matchAll(/\d+\([^()]*\)|(\d+)/g) - matches one or more digits (\d+) + ( (with \() + any zero or more chars other than ( and ) (with [^()]*) + \) (see \)), or (|) one or more digits captured into Group 1 ((\d+))
Array.from(..., x=> x[1] ?? "") - gets Group 1 value, or, if not assigned, just adds an empty string
.filter(Boolean) - removes empty strings.

Using several replacement regexes
var textA = `9(296,178),5,3(123),10
10,9(296,178),2,5,3(123),3(124,125)
10,7,5(296,293,444,1255),3(218),2,4
`
console.log('A', textA)
var textB = textA.replace(/\(.*?\),?/g, ';')
console.log('B', textB)
var textC = textB.replace(/^\d+|\d+$|\d*;\d*/gm, '')
console.log('C', textC)
var textD = textC.replace(/,+/g, ' ').trim(',')
console.log('D', textD)
With a loop
Here is a solution which splits the lines on comma and loops over the pieces:
var inside = false;
var result = [];
`9(296,178),5,3(123),10
10,9(296,178),2,5,3(123),3(124,125)
10,7,5(296,293,444,1255),3(218),2,4
`.split("\n").map(line => {
let pieceArray = line.split(",")
pieceArray.forEach((piece, k) => {
if (piece.includes('(')) {
inside = true
} else if (piece.includes(')')) {
inside = false
} else if (!inside && k > 0 && k < pieceArray.length-1 && !pieceArray[k-1].includes(')')) {
result.push(piece)
}
})
})
console.log(result)
It does print the expected result: ["5", "7"]

I need help getting the first n characters of a string up to when a number character starts

I'm working with a string where I need to extract the first n characters up to where numbers begin. What would be the best way to do this as sometimes the string starts with a number: 7EUSA8889er898 I would need to extract 7EUSA But other string examples would be SWFX74849948, I would need to extract SWFX from that string.
Not sure how to do this with regex my limited knowledge is blocking me at this point:
^(\w{4}) that just gets me the first four characters but I don't really have a stopping point as sometimes the string could be somelongstring292894830982 which would require me to get somelongstring

Using \w will match a word character which includes characters and digits and an underscore.
You could match an optional digit [0-9]? from the start of the string ^and then match 1+ times A-Za-z
^[0-9]?[A-Za-z]+
Regex demo
const regex = /^[0-9]?[A-Za-z]+/;
[
"7EUSA8889er898",
"somelongstring292894830982",
"SWFX74849948"
].forEach(s => console.log(s.match(regex)[0]));

Can use this regex code:
(^\d+?[a-zA-Z]+)|(^\d+|[a-zA-Z]+)
I try with exmaple and good worked:
1- somelongstring292894830982 -> somelongstring
2- 7sdfsdf5456 -> 7sdfsdf
3- 875werwer54556 -> 875werwer

If you want to create function where the RegExp is parametrized by n parameter, this would be
function getStr(str,n) {
var pattern = "\\d?\\w{0,"+n+"}";
var reg = new RegExp(pattern);
var result = reg.exec(str);
if(result[0]) return result[0].substr(0,n);
}

There are answers to this but here is another way to do it.
var string1 = '7EUSA8889er898';
var string2 = 'SWFX74849948';
var Extract = function (args) {
var C = args.split(''); // Split string in array
var NI = []; // Store indexes of all numbers
// Loop through list -> if char is a number add its index
C.map(function (I) { return /^\d+$/.test(I) === true ? NI.push(C.indexOf(I)) : ''; });
// Get the items between the first and second occurence of a number
return C.slice(NI[0] === 0 ? NI[0] + 1 : 0, NI[1]).join('');
};
console.log(Extract(string1));
console.log(Extract(string2));
Output
EUSA
SWFX7

Since it's hard to tell what you are trying to match, I'd go with a general regex
^\d?\D+(?=\d)

Retrieving several capturing groups recursively with RegExp

I have a string with this format:
#someID#tn#company#somethingNew#classing#somethingElse#With
There might be unlimited #-separated words, but definitely the whole string begins with #
I have written the following regexp, though it matches it, but I cannot get each #-separated word, and what I get is the last recursion and the first (as well as the whole string). How can I get an array of every word in an element separately?
(?:^\#\w*)(?:(\#\w*)+) //I know I have ruled out second capturing group with ?: , though doesn't make much difference.
And here is my Javascript code:
var reg = /(?:^\#\w*)(?:(\#\w*)+)/g;
var x = null;
while(x = reg.exec("#someID#tn#company#somethingNew#classing#somethingElse#With"))
{
console.log(x);
}
And here is the result (Firebug, console):
["#someID#tn#company#somet...sing#somethingElse#With", "#With"]
0
"#someID#tn#company#somet...sing#somethingElse#With"
1
"#With"
index
0
input
"#someID#tn#company#somet...sing#somethingElse#With"
EDIT :
I want an output like this with regular expression if possible:
["#someID", "#tn", #company", "#somethingNew", "#classing", "#somethingElse", "#With"]
NOTE that I want a RegExp solution. I know about String.split() and String operations.

You can use:
var s = '#someID#tn#company#somethingNew#classing#somethingElse#With'
if (s.substr(0, 1) == "#")
tok = s.substr(1).split('#');
//=> ["someID", "tn", "company", "somethingNew", "classing", "somethingElse", "With"]

You could try this regex also,
((?:#|#)\w+)
DEMO
Explanation:
() Capturing groups. Anything inside this capturing group would be captured.
(?:) It just matches the strings but won't capture anything.
#|# Literal # or # symbol.
\w+ Followed by one or more word characters.
OR
> "#someID#tn#company#somethingNew#classing#somethingElse#With".split(/\b(?=#|#)/g);
[ '#someID',
'#tn',
'#company',
'#somethingNew',
'#classing',
'#somethingElse',
'#With' ]

It will be easier without regExp:
var str = "#someID#tn#company#somethingNew#classing#somethingElse#With";
var strSplit = str.split("#");
for(var i = 1; i < strSplit.length; i++) {
strSplit[i] = "#" + strSplit[i];
}
console.log(strSplit);
// ["#someID", "#tn", "#company", "#somethingNew", "#classing", "#somethingElse", "#With"]

Javascript split function not correct worked with specific regex

I have a problem. I have a string - "\,str\,i,ing" and i need to split by comma before which not have slash. For my string - ["\,str\,i", "ing"]. I'm use next regex
myString.split("[^\],", 2)
but it's doesn't worked.

Well, this is ridiculous to avoid the lack of lookbehind but seems to get the correct result.
"\\,str\\,i,ing".split('').reverse().join('').split(/,(?=[^\\])/).map(function(a){
return a.split('').reverse().join('');
}).reverse();
//=> ["\,str\,i", "ing"]

Not sure about your expected output but you are specifying string not a regex, use:
var arr = "\,str\,i,ing".split(/[^\\],/, 2);
console.log(arr);
To split using regex, wrap your regex in /..../

This is not easily possible with js, because it does not support lookbehind. Even if you'd use a real regex, it would eat the last character:
> "xyz\\,xyz,xyz".split(/[^\\],/, 2)
["xyz\\,xy", "xyz"]
If you don't want the z to be eaten, I'd suggest:
var str = "....";
return str.split(",").reduce(function(res, part) {
var l = res.length;
if (l && res[l-1].substr(-1) == "\\" || l<2)
// ^ ^^ ^
// not the first was escaped limit
res[l-1] += ","+part;
else
res.push(part);
return;
}, []);

Reading between the lines, it looks like you want to split a string by , characters that are not preceded by \ characters.
It would be really great if JavaScript had a regular expression lookbehind (and negative lookbehind) pattern, but unfortunately it does not. What it does have is a lookahead ((?=) )and negative lookahead ((?!)) pattern. Make sure to review the documentation.
You can use these as a lookbehind if you reverse the string:
var str,
reverseStr,
arr,
reverseArr;
//don't forget to escape your backslashes
str = '\\,str\\,i,ing';
//reverse your string
reverseStr = str.split('').reverse().join('');
//split the array on `,`s that aren't followed by `\`
reverseArr = reverseStr.split(/,(?!\\)/);
//reverse the reversed array, and reverse each string in the array
arr = reverseArr.reverse().map(function (val) {
return val.split('').reverse().join('');
});

You picked a tough character to match- a forward slash preceding a comma is apt to disappear while you pass it around in a string, since '\,'==','...
var s= 'My dog, the one with two \\, blue \\,eyes, is asleep.';
var a= [], M, rx=/(\\?),/g;
while((M= rx.exec(s))!= null){
if(M[1]) continue;
a.push(s.substring(0, rx.lastIndex-1));
s= s.substring(rx.lastIndex);
rx.lastIndex= 0;
};
a.push(s);
/* returned value: (Array)
My dog
the one with two \, blue \,eyes
is asleep.
*/

Find something which will not be present in your original string, say "###". Replace "\\," with it. Split the resulting string by ",". Replace "###" back with "\\,".
Something like this:
<script type="text/javascript">
var s1 = "\\,str\\,i,ing";
var s2 = s1.replace(/\\,/g,"###");
console.log(s2);
var s3 = s2.split(",");
for (var i=0;i<s3.length;i++)
{
s3[i] = s3[i].replace(/###/g,"\\,");
}
console.log(s3);
</script>
See JSFiddle