The regular expressions I have tried include following:
1> var temp = "(.)\\1{2,}";
2> var temp = "^(?!.*(.)\\1{2,})";
testExp = new RegExp(temp);
The output I get is :
testExp.test("sss is true")
testExp.test("ss is false")
testexp.test("sdsdsd is false") //which should be true.
that is my regular expressions take into account only consecutive repeated characters and not others.
You may add .* before \1 (to match any 0+ chars other than line break chars) and use the following regex:
/(.)(?:.*\1){2,}/
Or, if there can be line breaks in the input string:
/([\s\S])(?:[\s\S]*\1){2,}/
See the regex demo. [\s\S] (or [^] in JS regex) will match any char while . matches any char but a line break char.
Details
(.) - capturing group #1 matching any 1 char
(?:.*\1){2,} - 2 or more consecutive occurrences of:
.* - any 0+ chars other than line break chars
\1 - backreference to Group 1 value (same char as captured in Group 1).
Try somethink like :
var str="sdsdsd";
var hasDuplicates = (/([a-zA-Z]).*?\1/).test(str)
alert("repeating string "+hasDuplicates);
var text = 'abcdeaf';
if (text.match(/(.).*\1/) {} else {}
Suppose I have a string
",,,a,,,,,b,,c,,,,d,,,,"
I want to convert this into
"a,b,c,d"
in 1 RegExp operation.
I can do it in 2 RegExp operations like
var str = ",,,a,,,b,,,,c,,,,,,,,d,,,,,,";
str = str.replace(/,+,/g,",").replace(/^,*|,*$/g, '');
is it possible to do this in 1 RegExp operation ?
You could use a regular expression, which are at start or are followed by a comma or at the and and replace it with an empty string.
/^,*|,(?=,|$)/g
1st Alternative ^,*
^ asserts position at start of the string
,* matches the character , literally (case sensitive)
* Quantifier — Matches between zero and unlimited times, as many times as possible, giving back as needed (greedy)
2nd Alternative ,+(?=,|$)
,+ matches the character , literally (case sensitive)
+ Quantifier — Matches between one and unlimited times, as many times as possible, giving back as needed (greedy)
Positive Lookahead (?=,|$)
Assert that the Regex below matches
1st Alternative ,
, matches the character , literally (case sensitive)
2nd Alternative $
$ asserts position at the end of the string
Global pattern flags
g modifier: global. All matches (don't return after first match)
var string = ",,,a,,,,,b,,c,,,,d,,,,";
console.log(string.replace(/^,*|,+(?=,|$)/g, ''));
The approach below returns expected result using two processes. .match() and template literal, which casts the encapsulated javascript expression to string when assigned to a variable.
You can use String.prototype.match() with RegExp /[^,]+/ to negate matching comma character ,, match one or more characters other than ,, including + in RegExp following character class where , is negated to match "abc" as suggested by #4castle; template literal to cast resulting array to string.
var str = ",,,a,,,b,,,,c,,,,,,,,d,,,efg,,,";
str = `${str.match(/[^,]+/g)}`;
console.log(str);
The following code only matches MN. How do I get it to match KDMN?
var str = ' New York Stock Exchange (NYSE) under the symbol "KDMN."';
var patt = new RegExp("symbol.+([A-Z]{2,5})");
var res = patt.exec(str);
console.log(res[1]);
You may use a lazy +? quantifier:
/symbol.+?([A-Z]{2,5})/
^
See the regex demo. If you keep the greedy .+, it will match as many characters as possible, and will only leave the minimum 2 chars for the next subpattern.
Or, I'd rather make this a bit more verbose:
/symbol\s+"([A-Z]{2,5})/
See another regex demo. The symbol matches a literal string symbol, \s+ will match 1 or more whitespaces, " will match a double quote, and ([A-Z]{2,5}) will capture 2 to 5 uppercase ASCII letters into Group 1.
I have and XML file with items that contain this string:
<field name="itemid">xx</field>
Where xx = a number from 50 to 250.
I need to remove the entire string from the whole file.
How would I do this with a Regex replace?
you can use this:
str = str.replace(/<.*>/g,'');
See an example for match here
var str = "<field name='itemid'>xx</field>";
str = str.replace(/<.*>/g, 'replaced');
console.log(str)
Explanation:
< matches the character < literally
.* matches any character (except newline)
Quantifier: * Between zero and unlimited times, as many times as possible, giving back as needed [greedy]
> matches the character > literally
g modifier: global. All matches (don't return on first match)
If you want to be more restrictive you can do this:
str = str.replace(/<field name\=\"\w*\">\d*<\/field>/g, '');
See an example for match here
var str = '<field name="test">200</field>';
str = str.replace(/<field name\=\"\w*\">\d*<\/field>/g, 'replaced');
console.log(str)
Explanation:
<field name matches the characters
\= matches the character = literally
\" matches the character " literally
\w* match any word character [a-zA-Z0-9_]
Quantifier: * Between zero and unlimited times, as many times as possible, giving back as needed [greedy]
\" matches the character " literally
> matches the character > literally
\d* match a digit [0-9]
- Quantifier: * Between zero and unlimited times, as many times as possible, giving back as needed [greedy]
< matches the character < literally
\/ matches the character / literally
field> matches the characters field> literally (case sensitive)
g modifier: global. All matches (don't return on first match)
When you replace a tag especially XML tag you must be sure that you capture everything from opening to closing tag. In this case RegExp should look back.
var re = /<(\S+)[^>]*>.*<\/\1>/g;
var m ='some text <ab id="aa">aa <p>qq</p> aa</ab>test test <p>paragraph </p>'.replace(re,'');
console.log(m);//some text test test
\1 matches (\S+)
\S+ one or more non-white-space characters
I have a password field in one form. Now I have to validate in such a way that the field value should be a 7 digits string along with a number. Otherwise it will return false.
Please help me.
Create regex first
Var regex = /\w{7}\d/i;
var yourvalue=$("#passwordid").value;
regex.test(yourvalue){
return true;
}
else{
return false
}
I’m sure there is a better way, but something like:
if ( /.{7}/.test(str) && /\d/.test(str) ) {
//OK
}
In your javascript you can use the RegExp object.
var regEx = new RegExp(pattern, modifiers);
or more simply:
var pattern = /pattern/modifiers;
E.g.
var password = "abcdefg1";
var pattern = /\w{7}\d/i;
var isMatch = pattern.test(password);
Here are some expressions:
[abc] Find any character between the brackets
[^abc] Find any character not between the brackets
[0-9] Find any digit from 0 to 9
[A-Z] Find any character from uppercase A to uppercase Z
[a-z] Find any character from lowercase a to lowercase z
[A-z] Find any character from uppercase A to lowercase z
[adgk] Find any character in the given set
[^adgk] Find any character outside the given set
(red|blue|green) Find any of the alternatives specified
Metacharacters:
. Find a single character, except newline or line terminator
\w Find a word character
\W Find a non-word character
\d Find a digit
\D Find a non-digit character
\s Find a whitespace character
\S Find a non-whitespace character
\b Find a match at the beginning/end of a word
\B Find a match not at the beginning/end of a word
\0 Find a NUL character
\n Find a new line character
\f Find a form feed character
\r Find a carriage return character
\t Find a tab character
\v Find a vertical tab character
\xxx Find the character specified by an octal number xxx
\xdd Find the character specified by a hexadecimal number dd
\uxxxx Find the Unicode character specified by a hexadecimal number xxxx
Quantifiers
n+ Matches any string that contains at least one n
n* Matches any string that contains zero or more occurrences of n
n? Matches any string that contains zero or one occurrences of n
n{X} Matches any string that contains a sequence of X n's
n{X,Y} Matches any string that contains a sequence of X to Y n's
n{X,} Matches any string that contains a sequence of at least X n's
n$ Matches any string with n at the end of it
^n Matches any string with n at the beginning of it
?=n Matches any string that is followed by a specific string n
?!n