In my text box, i should find (<LessThan Symobl> <character>) and replace with (<LessThan Symbol <space> <character>)

Example:

Input:

abc<xyz abc <abc

output:

abc< xyz abc < abc

From a string, i should find ([LessThanSymbol] [character]) and replace with ([LessThanSymbol] [space] [Character] ) in javascript

In my text box, i should find (<LessThan Symobl> <character>) and replace with (<LessThan Symbol <space> <character>)

Example:

Input:

abc<xyz abc <abc

output:

abc< xyz abc < abc

From a string, i should find ([LessThanSymbol] [character]) and replace with ([LessThanSymbol] [space] [Character] ) in javascript

• javascript

• I'm not sure I understand the desired result... – Brandon Frohbieter Commented Mar 3, 2011 at 20:56
• Re write the question please! – JAiro Commented Mar 3, 2011 at 20:57
• I have rewritten the question again below. I should probably need some regular expression that finds lessthan symbol followed by a character and replace with lessthan symbol followed by space followed by character. – SKumar Commented Mar 3, 2011 at 21:08
• There is an edit button under the question. Do not rewrite the question and post it as an answer. – gen_Eric Commented Mar 3, 2011 at 21:45

5 Answers 5

You can use a regular expression to find all < character that are followed by a non-space character, and insert a space:

s = s.replace(/<([^ ])/g, '< $1');

s = s.replace(/<(?=\S|$)/g, "< ");

What this means:

• You can guess what .replace() does and what the < represents. :-)
• (?=...) is a "positive look-ahead" — it means "followed by".
• \S matches any non-whitespace character (anything other than spaces, non-breaking spaces, tabs, carriage returns, and newlines).
• $ matches the end of the string.
• /.../g performs a global search/replace.

Using the look-ahead prevents you from having to use a capturing group ($1), using \S fixes your newline problem, and using $ keeps you from having a similar problem if the string ends with a less-than.

>>> "<foo < bar <\tbaz <\rquux <\nquuux <".replace(/<(?=\S|$)/g, "< ")
"< foo < bar <\tbaz <\rquux <\nquuux <"

The best I've found is this :

s = s.replace(/<(?!\s)(?!$)/g,'< ');

It means:

• (?!\s) - not followed by a whitespace (Negative Lookahead)
• (?!$) - not followed by the end of the string (Negative Lookahead)

You can also use a split() then a join() :

'abc<xyz abc <abc'.split('<').join('< ')

But there is a problem with this method : the trail character which is pleted with a non necessary space.

'abc<xyz abc <abc<'.split('<').join('< ')

gives this result

'abc< xyz abc < abc< '

Try something like...

var string_variable;
string_variable = "Replace text using javascript replace function within a javascript string variable";
string_variable = string_variable.replace(/javascript/g, "js");
alert(string_variable);

(see: http://www.kodyaz./articles/replace-all-occurrences-of-string-using-javascript-replace-function.aspx)

I found answer for this.

s= s.replace(/<([^ \n])/g, '< $1');

It inserts space after lessthan for all the occurances of lessthan followed by (nonspace and non new line)