Need to replace a string from a long string in javascript

Question

I have a long string

Full_str1 = '[email protected];[email protected];[email protected];[email protected];[email protected];';
removable_str2 = '[email protected];';

I need to have a replaced string which will have resultant Final string should look like,

[email protected];[email protected];[email protected];[email protected];

I tried with

str3 = Full_str1.replace(new RegExp('(^|\\b)' +removable_str2, 'g'),"");

but it resulted in

[email protected];[email protected];

Can you be a little more clear about what is the input and what is the expected output? What exactly you need to remove? — Calvin Nunes, Jan 10 '20 at 14:06
@CalvinNunes : I want to get rid of removable_str2 only from Full_str1. — Him Singhvi, Jan 10 '20 at 14:11
Need to be with regex? And does every word/site is separated by a `;` ? — Calvin Nunes, Jan 10 '20 at 14:15
Not compulsory with regex, yes every string is seperated by a ;. — Him Singhvi, Jan 10 '20 at 14:17
Without regex you can `split` the string by `;` then loop it and remove every value that matches exactly what you want to remove, in the end just `join` the string again. But probably with regex would be less code and less "trouble" — Calvin Nunes, Jan 10 '20 at 14:22
so do you have any regex suggestion? Yes I also thought of same of splitting and join back. — Him Singhvi, Jan 10 '20 at 14:26

score 2 · Accepted Answer · answered Jan 10 '20 at 14:29

Here a soluce using two separated regex for each case :

the str to remove is at the start of the string
the str to remove is inside or at the end of the string

PS : I couldn't perform it in one regex, because it would remove an extra ; in case of matching the string to remove inside of the global string.

const originalStr = '[email protected];[email protected];[email protected];[email protected];[email protected];[email protected];';
const toRemove = '[email protected];';

const epuredStr = originalStr
                      .replace(new RegExp(`^${toRemove}`, 'g'), '')
                      .replace(new RegExp(`;${toRemove}`, 'g'), ';');

console.log(epuredStr);

There is no need for two `replace` operations, see [my answer](https://stackoverflow.com/a/59684320/3832970). — Wiktor Stribiżew, Jan 10 '20 at 15:14

score 1 · Answer 2 · answered Jan 10 '20 at 15:10

First, the dynamic part must be escaped, else, . will match any char but a line break char, and will match ab@xyz§com;, too.

Next, you need to match this only at the start of the string or after ;. So, you may use

var Full_str1 = '[email protected];[email protected];[email protected];[email protected];[email protected];';
var removable_str2 = '[email protected];';
var rx = new RegExp("(^|;)" + removable_str2.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&'), "g");
console.log(Full_str1.replace(rx, "$1"));
// => [email protected];[email protected];[email protected];[email protected];

Replace "g" with "gi" for case insensitive matching.

See the regex demo. Note that (^|;) matches and captures into Group 1 start of string location (empty string) or ; and $1 in the replacement pattern restores this char in the result.

NOTE: If the pattern is known beforehand and you only want to handle [email protected]; pattern, use a regex literal without escaping, Full_str1.replace(/(^|;)ab@xyz\.com;/g, "$1").

score 0 · Answer 3 · answered Jan 10 '20 at 14:35

0

i don't find any particular description why you haven't tried like this it will give you desired result [email protected];[email protected];[email protected];[email protected];

const full_str1 = '[email protected];[email protected];[email protected];[email protected];[email protected];';
const removable_str2 = '[email protected];';

const result= full_str1.replace(removable_str2 , "");

console.log(result);

answered Jan 10 '20 at 14:35

ArunPratap

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The text `[email protected];` would be affected by your regex – Orelsanpls Jan 10 '20 at 14:39
@GrégoryNEUT got it – ArunPratap Jan 10 '20 at 14:43

Need to replace a string from a long string in javascript

3 Answers3