I have string with 2 or 3 words:
'apple grape lemon'
'apple grape'
I need to get first char from all words.
my regex:
/^(\w).*?\ (\w).*?\ ?(\w?).*?$/
For all strings this regex get only first char of 2 words.
How to fix?
You cannot do this with one regex (unless you are using .NET). But you can use a regex that matches one first character of a word, then get all the matches, and join them together:
var firstLetters = '';
var match = str.match(/\b\w/g)
if (match)
firstLetters = match.join('');
Of course if you just want to get the letters on their own, there is no need for the join, since the match will simply be an array containing all those letters.
You should not, that \w is not only letters, but digits and underscores, too.
If you work with javascript, you don't need to regex the hell out of a simple problem.
To get the first letter, just do that:
var aString = 'apple bee plant';
var anArray = aString.split(' ');
for(var aWord in anArray) {
var firstLetter = aWord.charAt(0);
}
Regular expressions are a regular language, such that you cannot have this kind of repetition in them. What you want is to cut the string into individual tokes (which can be done via regular expressions to match the separator) and then apply an regular expression on each token. To get the first char from each word it is faster to use a substring operation instead of a regular expression.
The problem with your regex is that the .*? after the second word eats up all the following content as everything afterwards is optional. This could be solved, but I personally think it makes things more complicated than required.
The most simple way would be:
firstLetters = (m = str.match(/\b\w/g))? m.join('') : '';
In regexp "words" don't mean only letters. In JavaScript \w is equals [A-Za-z0-9_]. So if you want only letters in your result, you can use [A-Za-z].
Related
I have an input string like this:
ABCDEFG[HIJKLMN]OPQRSTUVWXYZ
How can I replace each character in the string between the [] with an X (resulting in the same number of Xs as there were characters)?
For example, with the input above, I would like an output of:
ABCDEFG[XXXXXXX]OPQRSTUVWXYZ
I am using JavaScript's RegEx for this and would prefer if answers could be an implementation that does this using JavaScript's RegEx Replace function.
I am new to RegEx so please explain what you do and (if possible) link articles to where I can get further help.
Using replace() and passing the match to a function as parameter, and then Array(m.length).join("X") to generate the X's needed:
var str = "ABCDEFG[HIJKLMN]OPQRSTUVWXYZ"
str = str.replace(/\[[A-Z]*\]/g,(m)=>"["+Array(m.length-1).join("X")+"]")
console.log(str);
We could use also .* instead of [A-Z] in the regex to match any character.
About regular expressions there are thousands of resources, specifically in JavaScript, you could see Regular Expressions MDN but the best way to learn, in my opinion, is practicing, I find regex101 useful.
const str="ABCDEFG[HIJKLMN]OPQRSTUVWXYZ";
const run=str=>str.replace(/\[.*]/,(a,b,c)=>c=a.replace(/[^\[\]]/g,x=>x="X"));
console.log(run(str));
The first pattern /\[.*]/ is to select letters inside bracket [] and the second pattern /[^\[\]]/ is to replace the letters to "X"
We can observe that every individual letter you wish to match is followed by a series of zero or more non-'[' characters, until a ']' is found. This is quite simple to express in JavaScript-friendly regex:
/[A-Z](?=[^\[]*\])/g
regex101 example
(?= ) is a "positive lookahead assertion"; it peeks ahead of the current matching point, without consuming characters, to verify its contents are matched. In this case, "[^[]*]" matches exactly what I described above.
Now you can substitute each [A-Z] matched with a single 'X'.
You can use the following solution to replace a string between two square brackets:
const rxp = /\[.*?\]/g;
"ABCDEFG[HIJKLMN]OPQRSTUVWXYZ".replace(rxp, (x) => {
return x.replace(rxp, "X".repeat(x.length)-2);
});
I have string [FBWS-1] comes first than [FBWS-2]
In this string, I want to find all occurance of [FBWS-NUMBER]
I tried this :
var term = "[FBWS-1] comes first than [FBWS-2]";
alert(/^([[A-Z]-[0-9]])$/.test(term));
I want to get all the NUMBERS where [FBWS-NUMBER] string is matched.
But no success. I m new to regular expressions.
Can anyone help me please.
Note that ^([[A-Z]-[0-9]])$ matches start of a string (^), a [ or an uppercase ASCII letter (with [[A-Z]), -, an ASCII digit and a ] char at the end of the string. So,basically, strings like [-2] or Z-3].
You may use
/\[[A-Z]+-[0-9]+]/g
See the regex demo.
NOTE If you need to "hardcode" FBWS (to only match values like FBWS-123 and not ABC-3456), use it instead of [A-Z]+ in the pattern, /\[FBWS-[0-9]+]/g.
Details
\[ - a [ char
[A-Z]+ - one or more (due to + quantifier) uppercase ASCII letters
- - a hyphen
[0-9]+ - one or more (due to + quantifier) ASCII digits
] - a ] char.
The /g modifier used with String#match() returns all found matches.
JS demo:
var term = "[FBWS-1] comes first than [FBWS-2]";
console.log(term.match(/\[[A-Z]+-[0-9]+]/g));
You can use:
[\w+-\d]
var term = "[FBWS-1] comes first than [FBWS-2]";
alert(/[\w+-\d]/.test(term));
There are several reasons why your existing regex doesn't work.
You trying to match the beginning and ending of your string when you
actually want everything in between, don't use ^$
Your only trying to match one alpha character [A-Z] you need to make this greedy using the +
You can shorten [A-Z] and [0-9] by using the shorthands \w and \d. The brackets are generally unnecessary.
Note your code only returns a true false value (your using test) ATM it's unclear if this is what you want. You may want to use match with a global modifier (//g) instead of test to get a collection.
Here is an example using string.match(reg) to get all matches strings:
var term = "[FBWS-1] comes first than [FBWS-2]";
var reg1 = /\[[A-Z]+-[0-9]\]/g;
var reg2 = /\[FBWS-[0-9]\]/g;
var arr1 = term.match(reg1);
var arr2 = term.match(reg2)
console.log(arr1);
console.log(arr2);
Your regular expression /^([[A-Z]-[0-9]])$/ is wrong.
Give this regex a try, /\[FBWS-\d\]/g
remove the g if you only want to find 1 match, as g will find all similar matches
Edit: Someone mentioned that you want ["any combination"-"number"], hence if that's what you're looking for then this should work /\[[A-Z]+-\d\]/
Here is a string str = '.js("aaa").js("bbb").js("ccc")', I want to write a regular expression to return an Array like this:
[aaa, bbb, ccc];
My regular expression is:
var jsReg = /.js\(['"](.*)['"]\)/g;
var jsAssets = [];
var js;
while ((js = jsReg.exec(find)) !== null) {
jsAssets.push(js[1]);
}
But the jsAssets result is
[""aaa").js("bbb").js("ccc""]
What's wrong with this regular expression?
Use the lazy version of .*:
/\.js\(['"](.*?)['"]\)/g
^
And it would be better if you escape the first dot.
This will match the least number of characters until the next quote.
jsfiddle demo
If you want to allow escaped quotes, use something like this:
/\.js\(['"]((?:\\['"]|[^"])+)['"]\)/g
regex101 demo
I believe it can be done in one-liner with replace and match method calls:
var str = '.js("aaa").js("bbb").js("ccc")';
str.replace(/[^(]*\("([^"]*)"\)[^(]*/g, '$1,').match(/[^,]+/g);
//=> ["aaa", "bbb", "ccc"]
The problem is that you are using .*. That will match any character. You'll have to be a bit more specific with what you are trying to capture.
If it will only ever be word characters you could use \w which matches any word character. This includes [a-zA-Z0-9_]: uppercase, lowercase, numbers and an underscore.
So your regex would look something like this :
var jsReg = /js\(['"](\w*)['"]\)/g;
In
/.js\(['"](.*)['"]\)/g
matches as much as possible, and does not capture group 1, so it matches
"aaa").js("bbb").js("ccc"
but given your example input.
Try
/\.js\(('(?:[^\\']|\\.)*'|"(?:[\\"]|\\.)*"))\)/
To break this down,
\. matches a literal dot
\.js\( matches the literal string ".js("
( starts to capture the string.
[^\\']|\\. matches a character other than quote or backslash or an escaped non-line terminator.
(?:[\\']|\\.)* matches the body of a string
'(?:[\\']|\\.)*' matches a single quoted string
(...|...) captures a single quoted or double quoted string
)\) closes the capturing group and matches a literal close parenthesis
The second major problem is your loop.
You're doing a global match repeatedly which makes no sense.
Get rid of the g modifier, and then things should work better.
Try this one - http://jsfiddle.net/UDYAq/
var str = new String('.js("aaa").js("bbb").js("ccc")');
var regex = /\.js\(\"(.*?)\"\){1,}/gi;
var result = [];
result = str.match (regex);
for (i in result) {
result[i] = result[i].match(/\"(.*?)\"/i)[1];
}
console.log (result);
To be sure that matched characters are surrounded by the same quotes:
/\.js\((['"])(.*?)\1\)/g
I am having a difficult time getting a seemingly simple Regexp. I am trying to grab the last occurrences of word characters between square brackets in a string. My code:
pattern = /\[(\w+)\]/g;
var text = "item[gemstones_attributes][0][shape]";
if (pattern.test(text)) {
alert(RegExp.lastMatch);
}
The above code is outputting "gemstones_attributes", when I want it to output "shape". Why is this regexp not working, or is there something wrong with my approach to getting the last match? I'm sure that I am making an obvious mistake - regular expressions have never been my string suit.
Edit:
There are cases in which the string will not terminate with a right-bracket.
You can greedily match as much as possible before your pattern which will result in your group matching only the last match:
pattern = /.*\[(\w+)\]/g;
var text = "item[gemstones_attributes][0][shape]";
var match = pattern.exec(text);
if (match != null) alert(match[1]);
RegExp.lastMatch gives the match of the last regular expression. It isn't the last match in the text.
Regular expressions parse left to right and are greedy. So your regexp matches the first '[' it sees and grabs the words between it. When you call lastMatch it gives you the last pattern matched. What you need is to match everything you can first .* and then your pattern.
i think your problem is in your regex not in your src line .lastMatch.
Your regex returns just the first match of your square brackets and not all matches. You can try to add some groups to your regular expression - and normally you should get all matches.
krikit
Use match() instead of test()
if (text.match(pattern))
test() checks for a match inside a string. This is successfull after the first occurence, so there is no need for further parsing.
Hello can someone help me in jquery regex?
whew coz im stack here since last night and finally iv'e decided to ask some help :)
any here's my regex abd the string is in exg variable.. then i want to split the string each
matches[0] = 'eNortjI0sLBScgQDz3yTfK98XCdH59RKc4M8&+SSXFzzXFz3UE9H9yzfYMfCYtPiDLes0NSAXCL3nIj0osJcIvNCjwxLv6z8YhPTXFxv8&KSMNekjIrgqqzQvOJyy0zXNPMoZ4vS0PQS4+S0&IIgU7OssPIolygXJWtcMMMFXCch|eNortjI0sLRScgQDz3yTfK98XCfHXDBDjzx3X4&cXCLXygKn4tzsNCNcJ+NMk+xEM6Ok&OIq1+DcXFxLw8AwjyhHb480lyxTg&LkKv8sXw&zpCSnJE+XYo&EVH&3yKyAsMjEtKxSi4CIqlwigwL&giinXDC3wCiXKBcla1wwpPEmEA==|';
matches[1] = 'eNortjI0NLJScgQDz3yTfK98XCdH9yCPZJ&CiCpD36xcMMuSsLwox6qAwMqkUAPTlChHI8ugvDQL9zzjbBMfT8u8RIOgMgvnHJ9SpzynvFDfQAugijBLv6CgXDBT&0LzKMdI06BIf9OyKGd&U58kN19fV8colygXJWtcMNaqJP8=|';
var regex = /[a-zA-Z]+[0-9]+[/-=&_]+|/g;
var exg = 'eNortjI0sLBScgQDz3yTfK98XCdH59RKc4M8&+SSXFzzXFz3UE9H9yzfYMfCYtPiDLes0NSAXCL3nIj0osJcIvNCjwxLv6z8YhPTXFxv8&KSMNekjIrgqqzQvOJyy0zXNPMoZ4vS0PQS4+S0&IIgU7OssPIolygXJWtcMMMFXCch|eNortjI0sLRScgQDz3yTfK98XCfHXDBDjzx3X4&cXCLXygKn4tzsNCNcJ+NMk+xEM6Ok&OIq1+DcXFxLw8AwjyhHb480lyxTg&LkKv8sXw&zpCSnJE+XYo&EVH&3yKyAsMjEtKxSi4CIqlwigwL&giinXDC3wCiXKBcla1wwpPEmEA==|eNortjI0NLJScgQDz3yTfK98XCdH9yCPZJ&CiCpD36xcMMuSsLwox6qAwMqkUAPTlChHI8ugvDQL9zzjbBMfT8u8RIOgMgvnHJ9SpzynvFDfQAugijBLv6CgXDBT&0LzKMdI06BIf9OyKGd&U58kN19fV8colygXJWtcMNaqJP8=|eNodwdEKgjAUXDDQf&ELnLk57GnXJaiQq4do923YSuXqQKNgXx90zl4yxspE&TUhD21cMNVmqzQkKbdYGVQ6rfzrIy9+nEThYPBvhLU2bpezFs&YSw4H2xdEj+t4mzoVz8Rhuy&i1KTL4BCIx5mcd1tt7Bc16uT4A7goJkI=|eNodyN0KwiAUXDDgd9kb2CzGujoqyeaJFjmKc9fYMCGxkLWfpy&6Lr9UMsbLDP6qyGMdBZzOFRsmq3RYXYN8tW8kUQRdyJ7k4SNq2fntbJwP7QWQ5HOcSeQEKcd0TGzB3XXhY2&wV&6h7a27b17KGQImm9ZOpEhl+y9eOlwnaQ==|eNortjI0NLBScgQDz3yTfK98XCdHv3J3b9P80rwo54pwTy+DgkR3M3eXTMdAY6ekjChHD4PcFJ+KNIMg54Bko9IKxxC&XFyTQl+niqLc7NAkV6PIXCKjgFCD0FQTc4vSCuf0JP+SJIPcspKsKEdj48ys9CiXKBcla1wwr5gmBA==|eNortjI0sLBScgQDz3yTfK98XCdHp1KniMLwiNKglFxc71L3wqrAPEe3UF&PHMuq9BDPXDCflKTkkJDQCIM0s&B8rwxLR5co5ySXbJ9SY7dSH&+SyAqL7JQkV3cPX&NKc9OilKoU51ST&CQ&k6Ki0vIolygXJWtcMKhcMCZa|eNortjI0MLJScgQDz3yTfK98XCdHP5MoxySjJMfIFL&CEsuSUKNQv4LiSre8KKco56IUT3&L0CyfgMIox&IoXCevKFwns&R011THgMKsfLcoZ++MQo&0cNeyIPOqkPTIqrCqCstcMM+C8ChHz8goFyVrXDCmkyQg|eNortjI0NLJScgQDz3yTfK98XCdH&4z8yCin0szUgNwo54zkkBDTJB&TrIBA06S8XFxvr7SKyuDsKOeIZOPcsFA&&4woZ49UU&ekIKMq&7DURCOLimRjX9eKSmdDxxwXZ4&wjDT&lLDsJI&iqpB01yhcJ4v0KJcoFyVrXDA8ZVwnTQ==|eNortjI0MrBScgQDz3yTfK98XCdHLy&LSLfMyOxcIvfIioJit9Lc9NC04NK8NEvncHe&9Byv5MRwy8pC79ywgLT0SJ+qjORCC5PK0oh8i8yU0gpPR9PK7BJXn9SCxDznsEQXb7e8LLMCp+L8tMTyKJcoF7XUioLMotTi+Mw8WwMla1ww8SosXw==|eNortjI0NLRScgQDz3yTfK98XCdHr0pcJ+PAdP9sc+NcIvcyY4PEoNywyuyKzOQsC8twDx9Hg7TUkHyv7BDjMtPg3LwcjyinqlwiNxcXXCeXKFwn7wggEWmck59YHJhZ5Z4ZmF4R5eSfaFnkWuzpVFRglpxcXB7lEuWiZA1cMO+XJv4=|eNortjI0MLdScgQDz3yTfK98XCdHr7LgEpekEmO&xIBgo5CMoOSSKu&QDKPK5OziojS&&Bwvk&BK4yqLCFOjTNNcXC9Tz8C0jLzSkuCMYI88v8KIwORQi&TMQLM8i&B8Sy9Pl7QqXwt&gxQvrzLHKJcoFyVrXDCNviXB|eNortjI0NLRScgQDz3yTfK98XCdHn4pCp5yQxNIkM8MQ97SI0PLkoIqy9DJvZ3PXgPDwgKSIKKfwPKfi&CqvtAqTTNf0YMdwS8cM&yjH7Mr0omTTsLQqg&RcXLOK9Oz00LDgwijHCOeqyuC8KFwnf2fvSMcolygXJWtcMD&GXCfp|eNortjI0NLBScgQDz3yTfK98XCdHF6&gcEdTr5SiNO8KY1wnk1KLIE&&yowox+JcMB&XlGyzQH8&gwKvyIjyEMuyNI+ktMSQ7DDzdAsTA&fyKMckl&KS9HDDgNRKL0+jkCintLCStFwin+LcRC+PXFxcJ7+qwCiXKBcla1wwqjUmMg=='
if(regex.test(exg)) {
var matches = exg.match(regex);
for(var match in matches) {
alert(matches[match]);
}
} else {
alert("No matches found!");
}`
but my regex won't work whew can someone give me a right regex for it? :) please help..
Elias answer is probably the easiest way to do this but if you insist on regex then how about this:
var regex = /[a-zA-Z0-9\/-=&_+]+\|{0,1}/g
Explanation of your regex and why it doesn't work:
[a-zA-Z]+ // Match one or more a-z upper or lower case
[0-9]+ // *THEN* match one or more 0-9
[/-=&_]+ // *THEN* match one or more of these characters
| // *THEN* match a pipe
The problem here is that the letters, numbers and symbols in your search string are mixed together. Therefore they all need to go inside square brackets together so you match one or more of all of them together in any order. Yours puts them in a specific order, letters first, then numbers, then symbols.
The {0,1} on the end matches either zero or one pipe and will therefore catch the last match which does not have a pipe at the end.
Incidentely there's no such thing as JQuery regex. The regex functions are javascript.
erm... how about just using split like so marches = yourString.split('|');
this will return an array of strings, but the pipe char's will not be included, but just concat them to the substring if you need them.
You've missed a slash before |, so this may be what you want?
var regex = /[a-zA-Z0-9\/-=&_]+\|/g;