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I want to add a (variable) tag to values with regex, the pattern works fine with PHP but I have troubles implementing it into JavaScript.
The pattern is (value is the variable):
/(?!(?:[^<]+>|[^>]+<\/a>))\b(value)\b/is
I escaped the backslashes:
var str = $("#div").html();
var regex = "/(?!(?:[^<]+>|[^>]+<\\/a>))\\b(" + value + ")\\b/is";
$("#div").html(str.replace(regex, "" + value + ""));
But this seem not to be right, I logged the pattern and its exactly what it should be.
Any ideas?
To create the regex from a string, you have to use JavaScript's RegExp object.
If you also want to match/replace more than one time, then you must add the g (global match) flag. Here's an example:
var stringToGoIntoTheRegex = "abc";
var regex = new RegExp("#" + stringToGoIntoTheRegex + "#", "g");
// at this point, the line above is the same as: var regex = /#abc#/g;
var input = "Hello this is #abc# some #abc# stuff.";
var output = input.replace(regex, "!!");
alert(output); // Hello this is !! some !! stuff.
JSFiddle demo here.
In the general case, escape the string before using as regex:
Not every string is a valid regex, though: there are some speciall characters, like ( or [. To work around this issue, simply escape the string before turning it into a regex. A utility function for that goes in the sample below:
function escapeRegExp(stringToGoIntoTheRegex) {
return stringToGoIntoTheRegex.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
}
var stringToGoIntoTheRegex = escapeRegExp("abc"); // this is the only change from above
var regex = new RegExp("#" + stringToGoIntoTheRegex + "#", "g");
// at this point, the line above is the same as: var regex = /#abc#/g;
var input = "Hello this is #abc# some #abc# stuff.";
var output = input.replace(regex, "!!");
alert(output); // Hello this is !! some !! stuff.
JSFiddle demo here.
Note: the regex in the question uses the s modifier, which didn't exist at the time of the question, but does exist -- a s (dotall) flag/modifier in JavaScript -- today.
If you are trying to use a variable value in the expression, you must use the RegExp "constructor".
var regex = "(?!(?:[^<]+>|[^>]+<\/a>))\b(" + value + ")\b";
new RegExp(regex, "is")
I found I had to double slash the \b to get it working. For example to remove "1x" words from a string using a variable, I needed to use:
str = "1x";
var regex = new RegExp("\\b"+str+"\\b","g"); // same as inv.replace(/\b1x\b/g, "")
inv=inv.replace(regex, "");
You don't need the " to define a regular expression so just:
var regex = /(?!(?:[^<]+>|[^>]+<\/a>))\b(value)\b/is; // this is valid syntax
If value is a variable and you want a dynamic regular expression then you can't use this notation; use the alternative notation.
String.replace also accepts strings as input, so you can do "fox".replace("fox", "bear");
Alternative:
var regex = new RegExp("/(?!(?:[^<]+>|[^>]+<\/a>))\b(value)\b/", "is");
var regex = new RegExp("/(?!(?:[^<]+>|[^>]+<\/a>))\b(" + value + ")\b/", "is");
var regex = new RegExp("/(?!(?:[^<]+>|[^>]+<\/a>))\b(.*?)\b/", "is");
Keep in mind that if value contains regular expressions characters like (, [ and ? you will need to escape them.
I found this thread useful - so I thought I would add the answer to my own problem.
I wanted to edit a database configuration file (datastax cassandra) from a node application in javascript and for one of the settings in the file I needed to match on a string and then replace the line following it.
This was my solution.
dse_cassandra_yaml='/etc/dse/cassandra/cassandra.yaml'
// a) find the searchString and grab all text on the following line to it
// b) replace all next line text with a newString supplied to function
// note - leaves searchString text untouched
function replaceStringNextLine(file, searchString, newString) {
fs.readFile(file, 'utf-8', function(err, data){
if (err) throw err;
// need to use double escape '\\' when putting regex in strings !
var re = "\\s+(\\-\\s(.*)?)(?:\\s|$)";
var myRegExp = new RegExp(searchString + re, "g");
var match = myRegExp.exec(data);
var replaceThis = match[1];
var writeString = data.replace(replaceThis, newString);
fs.writeFile(file, writeString, 'utf-8', function (err) {
if (err) throw err;
console.log(file + ' updated');
});
});
}
searchString = "data_file_directories:"
newString = "- /mnt/cassandra/data"
replaceStringNextLine(dse_cassandra_yaml, searchString, newString );
After running, it will change the existing data directory setting to the new one:
config file before:
data_file_directories:
- /var/lib/cassandra/data
config file after:
data_file_directories:
- /mnt/cassandra/data
Much easier way: use template literals.
var variable = 'foo'
var expression = `.*${variable}.*`
var re = new RegExp(expression, 'g')
re.test('fdjklsffoodjkslfd') // true
re.test('fdjklsfdjkslfd') // false
Using string variable(s) content as part of a more complex composed regex expression (es6|ts)
This example will replace all urls using my-domain.com to my-other-domain (both are variables).
You can do dynamic regexs by combining string values and other regex expressions within a raw string template. Using String.raw will prevent javascript from escaping any character within your string values.
// Strings with some data
const domainStr = 'my-domain.com'
const newDomain = 'my-other-domain.com'
// Make sure your string is regex friendly
// This will replace dots for '\'.
const regexUrl = /\./gm;
const substr = `\\\.`;
const domain = domainStr.replace(regexUrl, substr);
// domain is a regex friendly string: 'my-domain\.com'
console.log('Regex expresion for domain', domain)
// HERE!!! You can 'assemble a complex regex using string pieces.
const re = new RegExp( String.raw `([\'|\"]https:\/\/)(${domain})(\S+[\'|\"])`, 'gm');
// now I'll use the regex expression groups to replace the domain
const domainSubst = `$1${newDomain}$3`;
// const page contains all the html text
const result = page.replace(re, domainSubst);
note: Don't forget to use regex101.com to create, test and export REGEX code.
var string = "Hi welcome to stack overflow"
var toSearch = "stack"
//case insensitive search
var result = string.search(new RegExp(toSearch, "i")) > 0 ? 'Matched' : 'notMatched'
https://jsfiddle.net/9f0mb6Lz/
Hope this helps
You can backreference like this in JavaScript:
var str = "123 $test 123";
str = str.replace(/(\$)([a-z]+)/gi, "$2");
This would (quite silly) replace "$test" with "test". But imagine I'd like to pass the resulting string of $2 into a function, which returns another value. I tried doing this, but instead of getting the string "test", I get "$2". Is there a way to achieve this?
// Instead of getting "$2" passed into somefunc, I want "test"
// (i.e. the result of the regex)
str = str.replace(/(\$)([a-z]+)/gi, somefunc("$2"));
Like this:
str.replace(regex, function(match, $1, $2, offset, original) { return someFunc($2); })
Pass a function as the second argument to replace:
str = str.replace(/(\$)([a-z]+)/gi, myReplace);
function myReplace(str, group1, group2) {
return "+" + group2 + "+";
}
This capability has been around since Javascript 1.3, according to mozilla.org.
Using ESNext, quite a dummy links replacer but just to show-case how it works :
let text = 'Visit http://lovecats.com/new-posts/ and https://lovedogs.com/best-dogs NOW !';
text = text.replace(/(https?:\/\/[^ ]+)/g, (match, link) => {
// remove ending slash if there is one
link = link.replace(/\/?$/, '');
return `${link.substr(link.lastIndexOf('/') +1)}`;
});
document.body.innerHTML = text;
Note: Previous answer was missing some code. It's now fixed + example.
I needed something a bit more flexible for a regex replace to decode the unicode in my incoming JSON data:
var text = "some string with an encoded 's' in it";
text.replace(/&#(\d+);/g, function() {
return String.fromCharCode(arguments[1]);
});
// "some string with an encoded 's' in it"
If you would have a variable amount of backreferences then the argument count (and places) are also variable. The MDN Web Docs describe the follwing syntax for sepcifing a function as replacement argument:
function replacer(match[, p1[, p2[, p...]]], offset, string)
For instance, take these regular expressions:
var searches = [
'test([1-3]){1,3}', // 1 backreference
'([Ss]ome) ([A-z]+) chars', // 2 backreferences
'([Mm][a#]ny) ([Mm][0o]r[3e]) ([Ww][0o]rd[5s])' // 3 backreferences
];
for (var i in searches) {
"Some string chars and many m0re w0rds in this test123".replace(
new RegExp(
searches[i]
function(...args) {
var match = args[0];
var backrefs = args.slice(1, args.length - 2);
// will be: ['Some', 'string'], ['many', 'm0re', 'w0rds'], ['123']
var offset = args[args.length - 2];
var string = args[args.length - 1];
}
)
);
}
You can't use 'arguments' variable here because it's of type Arguments and no of type Array so it doesn't have a slice() method.
is there any way to capture and replace all the commas within a string contained within quotation marks and not any commas outside of it. I'd like to change them to pipes, however this:
/("(.*?)?,(.*?)")/gm
is only getting the first instance:
JSBIN
If callbacks are okay, you can go for something like this:
var str = '"test, test2, & test3",1324,,,,http://www.asdf.com';
var result = str.replace(/"[^"]+"/g, function (match) {
return match.replace(/,/g, '|');
});
console.log(result);
//"test| test2| & test3",1324,,,,http://www.asdf.com
This is very convoluted compared to regular expression version, however, I wanted to do this if just for the sake of experiment:
var PEG = require("pegjs");
var parser = PEG.buildParser(
["start = seq",
"delimited = d:[^,\"]* { return d; }",
"quoted = q:[^\"]* { return q; }",
"quote = q:[\"] { return q; }",
"comma = c:[,] { return ''; }",
"dseq = delimited comma dseq / delimited",
"string = quote dseq quote",
"seq = quoted string seq / quoted quote? quoted?"].join("\n")
);
function flatten(array) {
return (array instanceof Array) ?
[].concat.apply([], array.map(flatten)) :
array;
}
flatten(parser.parse('foo "bar,bur,ber" baz "bbbr" "blerh')).join("");
// 'foo "barburber" baz "bbbr" "blerh'
I don't advise you to do this in this particular case, but maybe it will create some interest :)
PS. pegjs can be found here: (I'm not an author and have no affiliation, I simply like PEG) http://pegjs.majda.cz/documentation
With regex (i assume) or some other method, how can i convert things like:
marker-image or my-example-setting to markerImage or myExampleSetting.
I was thinking about just splitting by - then convert the index of that hypen +1 to uppercase. But it seems pretty dirty and was hoping for some help with regex that could make the code cleaner.
No jQuery...
Try this:
var camelCased = myString.replace(/-([a-z])/g, function (g) { return g[1].toUpperCase(); });
The regular expression will match the -i in marker-image and capture only the i. This is then uppercased in the callback function and replaced.
This is one of the great utilities that Lodash offers if you are enlightened and have it included in your project.
var str = 'my-hyphen-string';
str = _.camelCase(str);
// results in 'myHyphenString'
You can get the hypen and the next character and replace it with the uppercased version of the character:
var str="marker-image-test";
str.replace(/-([a-z])/g, function (m, w) {
return w.toUpperCase();
});
Here's my version of camelCase function:
var camelCase = (function () {
var DEFAULT_REGEX = /[-_]+(.)?/g;
function toUpper(match, group1) {
return group1 ? group1.toUpperCase() : '';
}
return function (str, delimiters) {
return str.replace(delimiters ? new RegExp('[' + delimiters + ']+(.)?', 'g') : DEFAULT_REGEX, toUpper);
};
})();
It handles all of the following edge cases:
takes care of both underscores and hyphens by default (configurable with second parameter)
string with unicode characters
string that ends with hyphens or underscore
string that has consecutive hyphens or underscores
Here's a link to live tests: http://jsfiddle.net/avKzf/2/
Here are results from tests:
input: "ab-cd-ef", result: "abCdEf"
input: "ab-cd-ef-", result: "abCdEf"
input: "ab-cd-ef--", result: "abCdEf"
input: "ab-cd--ef--", result: "abCdEf"
input: "--ab-cd--ef--", result: "AbCdEf"
input: "--ab-cd-__-ef--", result: "AbCdEf"
Notice that strings that start with delimiters will result in a uppercase letter at the beginning.
If that is not what you would expect, you can always use lcfirst.
Here's my lcfirst if you need it:
function lcfirst(str) {
return str && str.charAt(0).toLowerCase() + str.substring(1);
}
Use String's replace() method with a regular expression literal and a replacement function.
For example:
'uno-due-tre'.replace(/-./g, (m) => m[1].toUpperCase()) // --> 'unoDueTre'
Explanation:
'uno-due-tre' is the (input) string that you want to convert to camel case.
/-./g (the first argument passed to replace()) is a regular expression literal.
The '-.' (between the slashes) is a pattern. It matches a single '-' character followed by any single character. So for the string 'uno-due-tre', the pattern '-.' matches '-d' and '-t' .
The 'g' (after the closing slash) is a flag. It stands for "global" and tells replace() to perform a global search and replace, ie, to replace all matches, not just the first one.
(m) => m[1].toUpperCase() (the second argument passed to replace()) is the replacement function. It's called once for each match. Each matched substring is replaced by the string this function returns. m (the first argument of this function) represents the matched substring. This function returns the second character of m uppercased. So when m is '-d', this function returns 'D'.
'unoDueTre' is the new (output) string returned by replace(). The input string is left unchanged.
This doesn't scream out for a RegExp to me. Personally I try to avoid regular expressions when simple string and array methods will suffice:
let upFirst = word =>
word[0].toUpperCase() + word.toLowerCase().slice(1)
let camelize = text => {
let words = text.split(/[-_]/g) // ok one simple regexp.
return words[0].toLowerCase() + words.slice(1).map(upFirst)
}
camelize('marker-image') // markerImage
Here is my implementation (just to make hands dirty)
/**
* kebab-case to UpperCamelCase
* #param {String} string
* #return {String}
*/
function toUpperCamelCase(string) {
return string
.toLowerCase()
.split('-')
.map(it => it.charAt(0).toUpperCase() + it.substring(1))
.join('');
}
// Turn the dash separated variable name into camelCase.
str = str.replace(/\b-([a-z])/g, (_, char) => char.toUpperCase());
Here is another option that combines a couple answers here and makes it method on a string:
if (typeof String.prototype.toCamel !== 'function') {
String.prototype.toCamel = function(){
return this.replace(/[-_]([a-z])/g, function (g) { return g[1].toUpperCase(); })
};
}
Used like this:
'quick_brown'.toCamel(); // quickBrown
'quick-brown'.toCamel(); // quickBrown
You can use camelcase from NPM.
npm install --save camelcase
const camelCase = require('camelcase');
camelCase('marker-image'); // => 'markerImage';
camelCase('my-example-setting'); // => 'myExampleSetting';
Another take.
Used when...
var string = "hyphen-delimited-to-camel-case"
or
var string = "snake_case_to_camel_case"
function toCamelCase( string ){
return string.toLowerCase().replace(/(_|-)([a-z])/g, toUpperCase );
}
function toUpperCase( string ){
return string[1].toUpperCase();
}
Output: hyphenDelimitedToCamelCase
is also possible use indexOf with recursion for that task.
input some-foo_sd_dsd-weqe
output someFooSdDsdWeqe
comparison ::: measure execution time for two different scripts:
$ node camelCased.js
someFooSdDsdWeqe
test1: 2.986ms
someFooSdDsdWeqe
test2: 0.231ms
code:
console.time('test1');
function camelCased (str) {
function check(symb){
let idxOf = str.indexOf(symb);
if (idxOf === -1) {
return str;
}
let letter = str[idxOf+1].toUpperCase();
str = str.replace(str.substring(idxOf+1,idxOf+2), '');
str = str.split(symb).join(idxOf !== -1 ? letter : '');
return camelCased(str);
}
return check('_') && check('-');
}
console.log(camelCased ('some-foo_sd_dsd-weqe'));
console.timeEnd('test1');
console.time('test2');
function camelCased (myString){
return myString.replace(/(-|\_)([a-z])/g, function (g) { return g[1].toUpperCase(); });
}
console.log(camelCased ('some-foo_sd_dsd-weqe'));
console.timeEnd('test2');
Just a version with flag, for loop and without Regex:
function camelCase(dash) {
var camel = false;
var str = dash;
var camelString = '';
for(var i = 0; i < str.length; i++){
if(str.charAt(i) === '-'){
camel = true;
} else if(camel) {
camelString += str.charAt(i).toUpperCase();
camel = false;
} else {
camelString += str.charAt(i);
}
}
return camelString;
}
Use this if you allow numbers in your string.
Obviously the parts that begin with a number will not be capitalized, but this might be useful in some situations.
function fromHyphenToCamelCase(str) {
return str.replace(/-([a-z0-9])/g, (g) => g[1].toUpperCase())
}
function fromHyphenToCamelCase(str) {
return str.replace(/-([a-z0-9])/g, (g) => g[1].toUpperCase())
}
const str1 = "category-123";
const str2 = "111-222";
const str3 = "a1a-b2b";
const str4 = "aaa-2bb";
console.log(`${str1} => ${fromHyphenToCamelCase(str1)}`);
console.log(`${str2} => ${fromHyphenToCamelCase(str2)}`);
console.log(`${str3} => ${fromHyphenToCamelCase(str3)}`);
console.log(`${str4} => ${fromHyphenToCamelCase(str4)}`);
You can also use string and array methods; I used trim to avoid any spaces.
const properCamel = (str) =>{
const lowerTrim = str.trim().toLowerCase();
const array = lowerTrim.split('-');
const firstWord = array.shift();
const caps = array.map(word=>{
return word[0].toUpperCase() + word.slice(1);
})
caps.unshift(firstWord)
return caps.join('');
}
This simple solution takes into account these edge cases.
Single word
Single letter
No hyphen
More than 1 hyphen
const toCamelCase = (text) => text.replace(/(.)([^-|$]*)[-]*/g, (_,letter,word) => `${letter.toUpperCase()}${word.toLowerCase()}`)
I want to use str_replace or its similar alternative to replace some text in JavaScript.
var text = "this is some sample text that i want to replace";
var new_text = replace_in_javascript("want", "dont want", text);
document.write(new_text);
should give
this is some sample text that i dont want to replace
If you are going to regex, what are the performance implications in
comparison to the built in replacement methods.
You would use the replace method:
text = text.replace('old', 'new');
The first argument is what you're looking for, obviously. It can also accept regular expressions.
Just remember that it does not change the original string. It only returns the new value.
More simply:
city_name=city_name.replace(/ /gi,'_');
Replaces all spaces with '_'!
All these methods don't modify original value, returns new strings.
var city_name = 'Some text with spaces';
Replaces 1st space with _
city_name.replace(' ', '_'); // Returns: "Some_text with spaces" (replaced only 1st match)
Replaces all spaces with _ using regex. If you need to use regex, then i recommend testing it with https://regex101.com/
city_name.replace(/ /gi,'_'); // Returns: Some_text_with_spaces
Replaces all spaces with _ without regex. Functional way.
city_name.split(' ').join('_'); // Returns: Some_text_with_spaces
You should write something like that :
var text = "this is some sample text that i want to replace";
var new_text = text.replace("want", "dont want");
document.write(new_text);
The code that others are giving you only replace one occurrence, while using regular expressions replaces them all (like #sorgit said). To replace all the "want" with "not want", us this code:
var text = "this is some sample text that i want to replace";
var new_text = text.replace(/want/g, "dont want");
document.write(new_text);
The variable "new_text" will result in being "this is some sample text that i dont want to replace".
To get a quick guide to regular expressions, go here:
http://www.cheatography.com/davechild/cheat-sheets/regular-expressions/
To learn more about str.replace(), go here:
https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/replace
Good luck!
that function replaces only one occurrence.. if you need to replace
multiple occurrences you should try this function:
http://phpjs.org/functions/str_replace:527
Not necessarily.
see the Hans Kesting answer:
city_name = city_name.replace(/ /gi,'_');
Using regex for string replacement is significantly slower than using a string replace.
As demonstrated on JSPerf, you can have different levels of efficiency for creating a regex, but all of them are significantly slower than a simple string replace. The regex is slower because:
Fixed-string matches don't have backtracking, compilation steps, ranges, character classes, or a host of other features that slow down the regular expression engine. There are certainly ways to optimize regex matches, but I think it's unlikely to beat indexing into a string in the common case.
For a simple test run on the JS perf page, I've documented some of the results:
<script>
// Setup
var startString = "xxxxxxxxxabcxxxxxxabcxx";
var endStringRegEx = undefined;
var endStringString = undefined;
var endStringRegExNewStr = undefined;
var endStringRegExNew = undefined;
var endStringStoredRegEx = undefined;
var re = new RegExp("abc", "g");
</script>
<script>
// Tests
endStringRegEx = startString.replace(/abc/g, "def") // Regex
endStringString = startString.replace("abc", "def", "g") // String
endStringRegExNewStr = startString.replace(new RegExp("abc", "g"), "def"); // New Regex String
endStringRegExNew = startString.replace(new RegExp(/abc/g), "def"); // New Regexp
endStringStoredRegEx = startString.replace(re, "def") // saved regex
</script>
The results for Chrome 68 are as follows:
String replace: 9,936,093 operations/sec
Saved regex: 5,725,506 operations/sec
Regex: 5,529,504 operations/sec
New Regex String: 3,571,180 operations/sec
New Regex: 3,224,919 operations/sec
From the sake of completeness of this answer (borrowing from the comments), it's worth mentioning that .replace only replaces the first instance of the matched character. Its only possible to replace all instances with //g. The performance trade off and code elegance could be argued to be worse if replacing multiple instances name.replace(' ', '_').replace(' ', '_').replace(' ', '_'); or worse while (name.includes(' ')) { name = name.replace(' ', '_') }
var new_text = text.replace("want", "dont want");
hm.. Did you check replace() ?
Your code will look like this
var text = "this is some sample text that i want to replace";
var new_text = text.replace("want", "dont want");
document.write(new_text);
JavaScript has replace() method of String object for replacing substrings. This method can have two arguments. The first argument can be a string or a regular expression pattern (regExp object) and the second argument can be a string or a function. An example of replace() method having both string arguments is shown below.
var text = 'one, two, three, one, five, one';
var new_text = text.replace('one', 'ten');
console.log(new_text) //ten, two, three, one, five, one
Note that if the first argument is the string, only the first occurrence of the substring is replaced as in the example above. To replace all occurrences of the substring you need to provide a regular expression with a g (global) flag. If you do not provide the global flag, only the first occurrence of the substring will be replaced even if you provide the regular expression as the first argument. So let's replace all occurrences of one in the above example.
var text = 'one, two, three, one, five, one';
var new_text = text.replace(/one/g, 'ten');
console.log(new_text) //ten, two, three, ten, five, ten
Note that you do not wrap the regular expression pattern in quotes which will make it a string not a regExp object. To do a case insensitive replacement you need to provide additional flag i which makes the pattern case-insensitive. In that case the above regular expression will be /one/gi. Notice the i flag added here.
If the second argument has a function and if there is a match the function is passed with three arguments. The arguments the function gets are the match, position of the match and the original text. You need to return what that match should be replaced with. For example,
var text = 'one, two, three, one, five, one';
var new_text = text.replace(/one/g, function(match, pos, text){
return 'ten';
});
console.log(new_text) //ten, two, three, ten, five, ten
You can have more control over the replacement text using a function as the second argument.
In JavaScript, you call the replace method on the String object, e.g. "this is some sample text that i want to replace".replace("want", "dont want"), which will return the replaced string.
var text = "this is some sample text that i want to replace";
var new_text = text.replace("want", "dont want"); // new_text now stores the replaced string, leaving the original untouched
You can use
text.replace('old', 'new')
And to change multiple values in one string at once, for example to change # to string v and _ to string w:
text.replace(/#|_/g,function(match) {return (match=="#")? v: w;});
There are already multiple answers using str.replace() (which is fair enough for this question) and regex but you can use combination of str.split() and join() together which is faster than str.replace() and regex.
Below is working example:
var text = "this is some sample text that i want to replace";
console.log(text.split("want").join("dont want"));
If you really want a equivalent to PHP's str_replace you can use Locutus. PHP's version of str_replace support more option then what the JavaScript String.prototype.replace supports.
For example tags:
//PHP
$bodytag = str_replace("%body%", "black", "<body text='%body%'>");
//JS with Locutus
var $bodytag = str_replace(['{body}', 'black', '<body text='{body}'>')
or array's
//PHP
$vowels = array("a", "e", "i", "o", "u", "A", "E", "I", "O", "U");
$onlyconsonants = str_replace($vowels, "", "Hello World of PHP");
//JS with Locutus
var $vowels = ["a", "e", "i", "o", "u", "A", "E", "I", "O", "U"];
var $onlyconsonants = str_replace($vowels, "", "Hello World of PHP");
Also this doesn't use regex instead it uses for loops. If you not want to use regex but want simple string replace you can use something like this ( based on Locutus )
function str_replace (search, replace, subject) {
var i = 0
var j = 0
var temp = ''
var repl = ''
var sl = 0
var fl = 0
var f = [].concat(search)
var r = [].concat(replace)
var s = subject
s = [].concat(s)
for (i = 0, sl = s.length; i < sl; i++) {
if (s[i] === '') {
continue
}
for (j = 0, fl = f.length; j < fl; j++) {
temp = s[i] + ''
repl = r[0]
s[i] = (temp).split(f[j]).join(repl)
if (typeof countObj !== 'undefined') {
countObj.value += ((temp.split(f[j])).length - 1)
}
}
}
return s[0]
}
var text = "this is some sample text that i want to replace";
var new_text = str_replace ("want", "dont want", text)
document.write(new_text)
for more info see the source code https://github.com/kvz/locutus/blob/master/src/php/strings/str_replace.js
You have the following options:
Replace the first occurrence
var text = "this is some sample text that i want to replace and this i WANT to replace as well.";
var new_text = text.replace('want', 'dont want');
// new_text is "this is some sample text that i dont want to replace and this i WANT to replace as well"
console.log(new_text)
Replace all occurrences - case sensitive
var text = "this is some sample text that i want to replace and this i WANT to replace as well.";
var new_text = text.replace(/want/g, 'dont want');
// new_text is "this is some sample text that i dont want to replace and this i WANT to replace as well
console.log(new_text)
Replace all occurrences - case insensitive
var text = "this is some sample text that i want to replace and this i WANT to replace as well.";
var new_text = text.replace(/want/gi, 'dont want');
// new_text is "this is some sample text that i dont want to replace and this i dont want to replace as well
console.log(new_text)
More info -> here
In Javascript, replace function available to replace sub-string from given string with new one.
Use:
var text = "this is some sample text that i want to replace";
var new_text = text.replace("want", "dont want");
console.log(new_text);
You can even use regular expression with this function. For example, if want to replace all occurrences of , with ..
var text = "123,123,123";
var new_text = text.replace(/,/g, ".");
console.log(new_text);
Here g modifier used to match globally all available matches.
Method to replace substring in a sentence using React:
const replace_in_javascript = (oldSubStr, newSubStr, sentence) => {
let newStr = "";
let i = 0;
sentence.split(" ").forEach(obj => {
if (obj.toUpperCase() === oldSubStr.toUpperCase()) {
newStr = i === 0 ? newSubStr : newStr + " " + newSubStr;
i = i + 1;
} else {
newStr = i === 0 ? obj : newStr + " " + obj;
i = i + 1;
}
});
return newStr;
};
RunMethodHere
If you don't want to use regex then you can use this function which will replace all in a string
Source Code:
function ReplaceAll(mystring, search_word, replace_with)
{
while (mystring.includes(search_word))
{
mystring = mystring.replace(search_word, replace_with);
}
return mystring;
}
How to use:
var mystring = ReplaceAll("Test Test", "Test", "Hello");
Use JS String.prototype.replace first argument should be Regex pattern or String and Second argument should be a String or function.
str.replace(regexp|substr, newSubStr|function);
Ex:
var str = 'this is some sample text that i want to replace';
var newstr = str.replace(/want/i, "dont't want");
document.write(newstr); // this is some sample text that i don't want to replace
ES2021 / ES12
String.prototype.replaceAll()
is trying to bring the full replacement option even when the input pattern is a string.
const str = "Backbencher sits at the Back";
const newStr = str.replaceAll("Back", "Front");
console.log(newStr); // "Frontbencher sits at the Front"
1- String.prototype.replace()
We can do a full **replacement** only if we supply the pattern as a regular expression.
const str = "Backbencher sits at the Back";
const newStr = str.replace(/Back/g, "Front");
console.log(newStr); // "Frontbencher sits at the Front"
If the input pattern is a string, replace() method only replaces the first occurrence.
const str = "Backbencher sits at the Back";
const newStr = str.replace("Back", "Front");
console.log(newStr); // "Frontbencher sits at the Back"
2- You can use split and join
const str = "Backbencher sits at the Back";
const newStr = str.split("Back").join("Front");
console.log(newStr); // "Frontbencher sits at the Front"
function str_replace($old, $new, $text)
{
return ($text+"").split($old).join($new);
}
You do not need additional libraries.
In ECMAScript 2021, you can use replaceAll can be used.
const str = "string1 string1 string1"
const newStr = str.replaceAll("string1", "string2");
console.log(newStr)
// "string2 string2 string2"
simplest form as below
if you need to replace only first occurrence
var newString = oldStr.replace('want', 'dont want');
if you want ot repalce all occurenace
var newString = oldStr.replace(want/g, 'dont want');
Added a method replace_in_javascript which will satisfy your requirement. Also found that you are writing a string "new_text" in document.write() which is supposed to refer to a variable new_text.
let replace_in_javascript= (replaceble, replaceTo, text) => {
return text.replace(replaceble, replaceTo)
}
var text = "this is some sample text that i want to replace";
var new_text = replace_in_javascript("want", "dont want", text);
document.write(new_text);