Replace All Occurrences in a String

How do I replace all occurrences of a string in JavaScript?

In the latest versions of most popular browsers, you can use replaceAll
as shown here:

let result = "1 abc 2 abc 3".replaceAll("abc", "xyz");
// `result` is "1 xyz 2 xyz 3"

But check Can I use or another compatibility table first to make sure the browsers you're targeting have added support for it first.

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For Node.js and compatibility with older/non-current browsers:

Note: Don't use the following solution in performance critical code.

As an alternative to regular expressions for a simple literal string, you could use

str = "Test abc test test abc test...".split("abc").join("");

The general pattern is

str.split(search).join(replacement)

This used to be faster in some cases than using replaceAll and a regular expression, but that doesn't seem to be the case anymore in modern browsers.

Benchmark: https://jsben.ch/TZYzj

Conclusion:

If you have a performance-critical use case (e.g., processing hundreds of strings), use the regular expression method. But for most typical use cases, this is well worth not having to worry about special characters.

How do I replace all occurrences of a string in JavaScript?

In the latest versions of most popular browsers, you can use replaceAll
as shown here:

let result = "1 abc 2 abc 3".replaceAll("abc", "xyz");
// `result` is "1 xyz 2 xyz 3"

But check Can I use or another compatibility table first to make sure the browsers you're targeting have added support for it first.

---

For Node.js and compatibility with older/non-current browsers:

Note: Don't use the following solution in performance critical code.

As an alternative to regular expressions for a simple literal string, you could use

str = "Test abc test test abc test...".split("abc").join("");

The general pattern is

str.split(search).join(replacement)

This used to be faster in some cases than using replaceAll and a regular expression, but that doesn't seem to be the case anymore in modern browsers.

Benchmark: https://jsben.ch/TZYzj

Conclusion:

If you have a performance-critical use case (e.g., processing hundreds of strings), use the regular expression method. But for most typical use cases, this is well worth not having to worry about special characters.

replace all occurrences in a string

Use the global flag.

str.replace(/\n/g, '<br />');

Replace all occurrences of a substring in a string in C

For starters:

This line

strncpy(buffer, string, p-string);

not necessarily appends a 0-terminator to what had been copied to buffer.

The following line

strcat(buffer, replace);

however relies on buffer being 0-terminated.

As buffer had not been initialised and though the 0-terminator most likely misses the latter line may very well read beyond buffer's memory and with this invoke the infamous Undefined Behaviour.

Replace all instances of character in string in typescript?

Your second example is the closest. The first problem is your variable name, new, which happens to be one of JavaScript's reserved keywords (and is instead used to construct objects, like new RegExp or new Set). This means that your program will throw a Syntax Error.

Also, since the dot (.) is a special character inside regex grammar, you should escape it as \.. Otherwise you would end up with result == "xxxxxxxxxxxxxxxxxx", which is undesirable.

let email = "my.email@email.com"
let re = /\./gi;let result = email.replace(re, "x");
console.log(result)

Fastest method to replace all instances of a character in a string

The easiest would be to use a regular expression with g flag to replace all instances:

str.replace(/foo/g, "bar")

This will replace all occurrences of foo with bar in the string str. If you just have a string, you can convert it to a RegExp object like this:

var pattern = "foobar",
    re = new RegExp(pattern, "g");

how to replace all occurrences of a string inside tags using regex in java

We can try using a formal regex pattern matcher here. Match on the pattern <abc~a>(.*?)<abc~a>, and for each match append the tag with src replaced by abc. Here is a sample code:

String input = "Here is a src <abc~a>I am an src customer<abc~b> also another src here.";
Pattern p = Pattern.compile("<abc~a>(.*?)<abc~b>");
Matcher m = p.matcher(input);
StringBuffer buffer = new StringBuffer();
  
while(m.find()) {
    String replace = "<abc~a>" + m.group(1).replaceAll("\\bsrc\\b", "abc") + "<abc~b>";
    m.appendReplacement(buffer, replace);
}
m.appendTail(buffer);

System.out.println(buffer.toString());

This prints:

Here is a src <abc~a>I am an abc customer<abc~b> also another src here.

Note that in many other languages we could have used a regex callback function. But core Java does not support this functionality, so we have to iterate over the entire input.

Why doesn't replace () change all occurrences?

It did make all replacements (that's what .replace() does in Python unless specified otherwise), but some of these replacements inadvertently introduced new instances of GAGA. Take the beginning of your string:

TGCGAGAA

There's GAGA at indices 3-6. If you replace that with AGAG, you get

TGCAGAGA

So the last G from that AGAG, together with the subsequent A that was already there before, forms a new GAGA.

Replace all except the first occurrence of a substring in Python?

With additional "reversed" substitution step:

s = "SELECT sdfdsf SELECT sdrrr SELECT 5445ff"
res = s.replace("SELECT", "@@@SELECT").replace("@@@SELECT", "SELECT", 1)
print(res)

The output:

SELECT sdfdsf @@@SELECT sdrrr @@@SELECT 5445ff

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A more sophisticated, but ensuring target word boundaries, could be as below:

import re

def make_replacer():
    rpl = ''
    def inner(m):
        nonlocal rpl
        res = rpl + m.group()
        rpl = '@@@'
        return res
    return inner

s = "SELECT sdfdsf SELECT sdrrr SELECT 5445ff"
res = re.sub(r'\bSELECT\b', make_replacer(), s)
print(res)   # SELECT sdfdsf @@@SELECT sdrrr @@@SELECT 5445ff

How to replace all occurrences of a string except the first one in JavaScript?

You can pass a function to String#replace, where you can specify to omit replacing the first occurrence. Also make your first parameter of replace a regex to match all occurrences.

Demo

let str = 'hello world hello world hello world hello',    i = 0;    str = str.replace(/world/g, m  => !i++ ? m : '');console.log(str);

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