This question already has answers here:
How do I replace an asterisk in Javascript using replace()?
(6 answers)
Closed 7 years ago.
I am trying to replace the same string *a*a consistently with *a.
Tried many variations of something like this, but none really worked:
s = s.replace( /\b*a*a\b/g, "*a");
So far running this leads to all xzy*a being replaced with xyz
* is a special regex character. If you want to match only an actual asterisk, then you have to escape it like this:
s = s.replace( /\*a\*a/g, "*a");
Working demo: http://jsfiddle.net/jfriend00/gvgshwyz/
An asterisk is a special regex character.
You just have to escape it like this: \*a in place of *a
Related
This question already has answers here:
Getting content between curly braces in JavaScript with regex
(5 answers)
Closed 2 years ago.
I need to match a specific regex syntax and split them so that we can match them to an equivalent value from a dictionary.
Input:
{Expr "string"}
{Expr "string"}{Expr}
Current code:
value.match(/\{.*\}$/g)
Desired Output:
[{Expr "string"}]
[{Expr "string"},{Expr}]
Use a non-greedy quantifier .*?. And don't use $, because that forces it to match all the way to the end of the string.
value = '{Expr "string"}{Expr}'
console.log(value.match(/\{.*?\}/g));
One option, assuming your version of JavaScript support it, would be to split the input on the following regex pattern:
(?<=\})(?=\{)
This says to split at each }{ junction between two terms.
var input = "{Expr \"string\"}{Expr}";
var parts = input.split(/(?<=\})(?=\{)/);
console.log(parts);
This question already has answers here:
Replace forward slash "/ " character in JavaScript string?
(9 answers)
Why this javascript regex doesn't work?
(1 answer)
Closed 4 years ago.
I have a string field 01/01/1986 and I am using replace method to replace all occurrence of / with -
var test= '01/01/1986';
test.replace('//g','-')
but it does't give desire result. Any pointer would be helpful.
You just have a couple issues: don't put the regex in quotes. That turns it into a string instead of a regex and looks for that literal string. Then use \/ to escape the /:
var test= '01/01/1986';
console.log(test.replace(/\//g,'-'))
A quick way is to use split and join.
var test= '01/01/1986';
var result = test.split('/').join('-');
console.log(result);
Note too that you need to save the result. The original string itself will never be modified.
This question already has answers here:
How can I replace a string in parentheses using a regex?
(4 answers)
Closed 7 years ago.
I need to replace the text between two parentheses using Regex in Javascript. For example:
var x = "I need to go (now)";
I need to replace 'now' with 'tomorrow'. I tried this, but it didn't work:
x.replace(/\(now)\b/g, 'tomorrow');
"I need to know (now)".replace(/\(now\)/g, 'tomorrow');
You don't need the \b and you need to escape the second ).
This question already has answers here:
How to split a long regular expression into multiple lines in JavaScript?
(11 answers)
Closed 8 years ago.
This one seems like it has a very simple answer, yet I can't find it anywhere. I have a regular expression that is quite large, how do I put in some line breaks in the expression itself so I don't have to keep scrolling horizontally through the code to see it all?
I don't normally use word-wrap, and the IDE I'm using doesn't even offer it anyway.
A line break in a string would normally be a \ at the end of the line :
var mystring "my string \
is on more \
than one line";
var re = new RegExp(mystring, "gim");
You could use RegExp and .join() to convert and concat a string.
var myRegExp = RegExp(['/^([a-zA-Z0-9_.-])+'
,'#([a-zA-Z0-9_.-])+'
,'\.([a-zA-Z])+([a-zA-Z])+/'].join(''));
The answer has been linked to here as well.
How to split a long regular expression into multiple lines in JavaScript?
This question already has answers here:
Replace method doesn't work
(4 answers)
Closed 4 years ago.
I'm trying to further my understanding of regular expressions in JavaScript.
So I have a form that allows a user to provide any string of characters. I'd like to take that string and remove any character that isn't a number, parenthesis, +, -, *, /, or ^. I'm trying to write a negating regex to grab anything that isn't valid and remove it. So far the code concerning this issue looks like this:
var pattern = /[^-\+\(\)\*\/\^0-9]*/g;
function validate (form) {
var string = form.input.value;
string.replace(pattern, '');
alert(string);
};
This regex works as intended on http://www.infobyip.com/regularexpressioncalculator.php regex tester, but always alerts with the exact string I supply without making any changes in the calculator. Any advice or pointers would be greatly appreciated.
The replace method doesn't modify the string. It creates a new string with the result of the replacement and returns it. You need to assign the result of the replacement back to the variable:
string = string.replace(pattern, '');