Develop Reference

Regex split comma except escaped [duplicate]

I have this string:
a\,bcde,fgh,ijk\,lmno,pqrst\,uv
I need a JavaScript function that will split the string by every , but only those that don't have a \ before them
How can this be done?

Here's the shortest thing I could come up with:
'a\\,bcde,fgh,ijk\\,lmno,pqrst\\,uv'.replace(/([^\\]),/g, '$1\u000B').split('\u000B')
The idea behind is to find every place where comma isn't prefixed with a backslash, replace those with string that is uncommon to come up in your strings and then split by that uncommon string.
Note that backslashes before commas have to be escaped using another backslash. Otherwise, javascript treats form \, as escaped comma and produce simply a comma out of it! In other words if you won't escape the backslash, javascript sees this: a\,bcde,fgh,ijk\,lmno,pqrst\,uv as this a,bcde,fgh,ijk,lmno,pqrst,uv.

Since regular expressions in JavaScript does not support lookbehinds, I'm not going to cook up a giant hack to mimic this behavior. Instead, you can just split() on all commas (,) and then glue back the pieces that shouldn't have been split in the first place.
Quick 'n' dirty demo:
var str = 'a\\,bcde,fgh,ijk\\,lmno,pqrst\\,uv'.split(','), // Split on all commas
out = []; // Output
for (var i = 0, j = str.length - 1; i < j; i++) { // Iterate all but last (last can never be glued to non-existing next)
var curr = str[i]; // This piece
if (curr.charAt(curr.length - 1) == '\\') { // If ends with \ ...
curr += ',' + str[++i]; // ... glue with next and skip next (increment i)
}
out.push(curr); // Add to output
}

Another ugly hack around the lack of look-behinds:
function rev(s) {
return s.split('').reverse().join('');
}
var s = 'a\\,bcde,fgh,ijk\\,lmno,pqrst\\,uv';
// Enter bizarro world...
var r = rev(s);
// Split with a look-ahead
var rparts = r.split(/,(?!\\)/);
// And put it back together with double reversing.
var sparts = [ ];
while(rparts.length)
sparts.push(rev(rparts.pop()));
for(var i = 0; i < sparts.length; ++i)
$('#out').append('<pre>' + sparts[i] + '</pre>');
Demo: http://jsfiddle.net/ambiguous/QbBfw/1/
I don't think I'd do this in real life but it works even if it does make me feel dirty. Consider this a curiosity rather than something you should really use.

In case if need remove backslashes also:
var test='a\\.b.c';
var result = test.replace(/\\?\./g, function (t) { return t == '.' ? '\u000B' : '.'; }).split('\u000B');
//result: ["a.b", "c"]

In 2022 most of browsers support lookbehinds:
https://caniuse.com/js-regexp-lookbehind
Safari should be your only concern.
With a lookbehind you can split your string this way:
"a\\,bcde,fgh,ijk\\,lmno,pqrst\\,uv".split(/(?<!\\),/)
// => ['a\\,bcde', 'fgh', 'ijk\\,lmno', 'pqrst\\,uv']

You can use regex to do the split.
Here is the link to regex in javascript http://www.w3schools.com/jsref/jsref_obj_regexp.asp
Here is the link to other post where the author have used regex for split Javascript won't split using regex
From the first link if you note you can create a regular expression using
?!n Matches any string that is not followed by a specific string n
[,]!\\

How to remove \n after JSON.stringfy?

I parse the data from website and try to change to a json object.
Here is my function:
function outPutJSON() {
for (var i = 0; i < movieTitle.length; i++) {
var handleN = movieContent[i];
console.log('===\n');
console.log(handleN);
data.movie.push({
mpvieTitle: movieTitle[i],
movieEnTitle: movieEnTitle[i],
theDate: theDate[i],
theLength: theLength[i],
movieVersion: movieVersion[i],
youtubeId: twoId[i],
content: movieContent[i]
});
};
return JSON.stringify(data);
}
console.log will print movieContent[0] like:
but i return JSON.stringfy(data);
it will become:
There are so many /n i want to remove it.
I try to change return JSON.stringfy(data); to this:
var allMovieData = JSON.stringify(data);
allMovieData = allMovieData.replace(/\n/g, '');
return allMovieData;
It's not working the result is the same.
How to remove /n when i use JSON.stringfy() ?
Any help would be appreciated . Thanks in advance.

In your data screenshots, you literally see "\n".
This probably means that the actual string doesn't contain a newline character (\n), but a escaped newline character (\\n).
A newline character would have been rendered as a linebreak. You wouldn't see the \n.
To remove those, use .replace(/\\n/g, '') instead of .replace(/\n/g, '')

just :=>
JSON.stringify(JSON.parse(<json object>))

JSON.stringify converts new lines (\n) and tab (\t) chars into string, so, when you will try to parse it, the string will contain those again.
So, you need to search the string \n, you can do that with something like that.
const stringWithNewLine = {
x: `this will conatin
new lines`
};
const json = JSON.stringify(stringWithNewLine);
console.log(json.replace(/\\n/g, ''))

I know this is an old question but it is always good to have options. You can use a string literal as a simple wrapper. The string literal will honor the string's line breaks, empty spaces etc. Like:
let jsonAsPrettyString = `${JSON.stringify(jsonObject, null, 2)}`;

Regex to validate a texarea input which must be URLs separated by new lines

I am trying to create a regex which will ultimately be used with Google Forms to validate a texarea input.
The rule is,
Input area can have one or more URLs (http or https)
Each URL must be separated either by one or more new lines
Each line which has text, must be a single valid URL
Last URL may have or may not have new line character/s after it
Till now, I have written this regex ^(https?://.+[\r\n]+)*(https?://.+[\r\n]+?)$ but the problem is that if a line has more than 1 url, it validates that too.
Here is my testing playground: http://goo.gl/YPdvBH.

Here is what you are looking for
Demo , Demo with your URLS
function validate(ele) {
str = ele.value;
str = str.replace(/\r/g, "");
while (/\s\n/.test(str)) {
str = str.replace(/\s\n/g, "\n");
}
while (/\n\n/.test(str)) {
str = str.replace(/\n\n/g, "\n");
}
ele.value = str;
str = str.replace(/\n/g, "_!_&_!_").split("_!_&_!_")
var result = [], counter = 0;
for (var i = 0; i < str.length; i++) {
str[i] = str[i].replace(/(?:(?:^|\n)\s+|\s+(?:$|\n))/g, '').replace(/\s+/g, ' ');
if(str[i].length !== 0){
if (isValidAddress(str[i])) {
result.push(str[i]);
}
counter += 1;
}
}
function isValidAddress(s) {
return /^(https?|ftp):\/\/(((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:)*#)?(((\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5])\.(\d|[1-9]\d|1\d\d|2[0-4]\d|25[0-5]))|((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?)(:\d*)?)(\/((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|#)+(\/(([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|#)*)*)?)?(\?((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|#)|[\uE000-\uF8FF]|\/|\?)*)?(\#((([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(%[\da-f]{2})|[!\$&'\(\)\*\+,;=]|:|#)|\/|\?)*)?$/i.test(s)
}
return (result.length === str.length);
}
var ele = document.getElementById('urls');
validate(ele);

This is closer to the regex you are looking for:
^(https?://[\S]+[\r\n]+)*(https?://[\S]+[\r\n]+?)$
The difference between your regex and this one is that you use .+ which will match all characters except newline whereas I use [\S]+ (note it is a capital S) which will match all non-whitespace characters. So, this doesn't match more than one token on one line. Hence, on each line you can match at max one token and that must be of the form that you have defined.
For a regex to match a single URL, look at this question on StackOverflow:
What is the best regular expression to check if a string is a valid URL?
I don't know whether google-forms have a length limit. But if they have, it is sure to almost bounce into it.

If i understand right - in your regexp missing m flag for multiline, so you need something like this
/^(https?://.+this your reg exp for one url)$/m
sample with regexp from Javascript URL validation regex
/^(ht|f)tps?:\/\/[a-z0-9-\.]+\.[a-z]{2,4}\/?([^\s<>\#%"\,\{\}\\|\\\^\[\]`]+)?$/m

Javascript Remove strings in beginning and end

base on the following string
...here..
..there...
.their.here.
How can i remove the . on the beginning and end of string like the trim that removes all spaces, using javascript
the output should be
here
there
their.here

These are the reasons why the RegEx for this task is /(^\.+|\.+$)/mg:
Inside /()/ is where you write the pattern of the substring you want to find in the string:
/(ol)/ This will find the substring ol in the string.
var x = "colt".replace(/(ol)/, 'a'); will give you x == "cat";
The ^\.+|\.+$ in /()/ is separated into 2 parts by the symbol | [means or]
^\.+ and \.+$
^\.+ means to find as many . as possible at the start.
^ means at the start; \ is to escape the character; adding + behind a character means to match any string containing one or more that character
\.+$ means to find as many . as possible at the end.
$ means at the end.
The m behind /()/ is used to specify that if the string has newline or carriage return characters, the ^ and $ operators will now match against a newline boundary, instead of a string boundary.
The g behind /()/ is used to perform a global match: so it find all matches rather than stopping after the first match.
To learn more about RegEx you can check out this guide.

Try to use the following regex
var text = '...here..\n..there...\n.their.here.';
var replaced = text.replace(/(^\.+|\.+$)/mg, '');

Here is working Demo
Use Regex /(^\.+|\.+$)/mg
^ represent at start
\.+ one or many full stops
$ represents at end
so:
var text = '...here..\n..there...\n.their.here.';
alert(text.replace(/(^\.+|\.+$)/mg, ''));

Here is an non regular expression answer which utilizes String.prototype
String.prototype.strim = function(needle){
var first_pos = 0;
var last_pos = this.length-1;
//find first non needle char position
for(var i = 0; i<this.length;i++){
if(this.charAt(i) !== needle){
first_pos = (i == 0? 0:i);
break;
}
}
//find last non needle char position
for(var i = this.length-1; i>0;i--){
if(this.charAt(i) !== needle){
last_pos = (i == this.length? this.length:i+1);
break;
}
}
return this.substring(first_pos,last_pos);
}
alert("...here..".strim('.'));
alert("..there...".strim('.'))
alert(".their.here.".strim('.'))
alert("hereagain..".strim('.'))
and see it working here : http://jsfiddle.net/cettox/VQPbp/

Slightly more code-golfy, if not readable, non-regexp prototype extension:
String.prototype.strim = function(needle) {
var out = this;
while (0 === out.indexOf(needle))
out = out.substr(needle.length);
while (out.length === out.lastIndexOf(needle) + needle.length)
out = out.slice(0,out.length-needle.length);
return out;
}
var spam = "this is a string that ends with thisthis";
alert("#" + spam.strim("this") + "#");
Fiddle-ige

Use RegEx with javaScript Replace
var res = s.replace(/(^\.+|\.+$)/mg, '');

We can use replace() method to remove the unwanted string in a string
Example:
var str = '<pre>I'm big fan of Stackoverflow</pre>'
str.replace(/<pre>/g, '').replace(/<\/pre>/g, '')
console.log(str)
output:
Check rules on RULES blotter

Extract strings in a .txt file with javascript

I have a .txt file with this structure:
chair 102
file 38
green 304
... ...
It has 140.000 elements.
Before introducing the numbers I used javascript and jQuery:
$(function () {
$.get('/words.txt', function (data) {
words = data.split('\n');
});
But because I have now numbers how could I treat separately the strings and the numbers?

Since this helped, I'll post as an answer:
Your format is <word><space><num>\n
You split on new line, so now you have an array of <word><space><num> which you should be able to split on space.
Then you can get the word part as myarray[0] and the number part as myarray[1].

you could split at each new line and then split each element at space, but this will gives you array of array of words .
you could replace line with space and then split at space
ie:
words = data.replace(/\n/g,' ').split(' ');

An efficient way of handling this problem is to replace all the line breaks with spaces, then split the resulting string by the spaces. Then use what you know about the position of the elements to determine whether you're dealing with a number or a string:
var resultArr = data.replace(/\n/g, " ").split(" ")
for(var i = 0; i < resultArr.length; i++) {
if(i % 2) {
// even indexes represent the word
console.info("word = " + resultArr[i]);
} else {
// odd indexes represent the number
console.info("number = " + resultArr[i]);
}
}
Depending on whether or not there's a line break at the end of the set, you may need to handle that case by looking for an empty string.