Develop Reference

Extract words with RegEx

I am new with RegEx, but it would be very useful to use it for my project. What I want to do in Javascript is this :
I have this kind of string "/this/is/an/example" and I would like to extract each word of that string, that is to say :
"/this/is/an/example" -> this, is, an, example. And then use each word.
Up to now, I did :
var str = "/this/is/a/test";
var patt1 = /\/*/g;
var result = str.match(patt1);
document.getElementById("demo").innerHTML = result;
and it returns me : /,,,,,/,,,/,,/,,,,,
I know that I will have to use .slice function next if I can identify the position of each "/" by using search for instance but using search it only returns me the index of the first "/" that is to say in this case 0.
I cannot find out.
Any Idea ?
Thanks in advance !

Use split()
The split() method splits a String object into an array of strings by separating the string into substrings, using a specified separator string to determine where to make each split.
var str = "/this/is/a/test";
var array = str.split('/');
console.log(array);
In case you want to do with regex.
var str = "/this/is/a/test";
var patt1 = /(\w+)/g;
var result = str.match(patt1)
console.log(result);

Well I guess it depends on your definition of 'word', there is a 'word character' match which might be what you want:
var patt1 = /(\w+)/g;
Here is a working example of the regex
Full JS example:
var str = "/this/is/a/test";
var patt1 = /(\w+)/g;
var match = str.match(patt1);
var output = match.join(", ");
console.log(output);

You can use this regex: /\b[^\d\W]+\b/g, to have a specific word just access the index in the array. e.g result[0] == this
var str = "/this/is/a/test";
var patt1 = /\b[^\d\W]+\b/g;
var result = str.match(patt1);
document.getElementById("demo").innerHTML = result;
<span id="demo"></span>

Need a Regex to get select name

I have a variable which stores some string.
eg var string = '<select mltiple="" name="multi_select_frV6Yzed4dxzsotOvJ5cXg9Aa[]" aria-required="true">';
i want to get multi_select_frV6Yzed4dxzsotOvJ5cXg9Aa[] using regex expression. Thanks in advance

You can do it this way as well (not using any regex here)
var string = '<select mltiple="" name="multi_select_frV6Yzed4dxzsotOvJ5cXg9Aa[]" aria-required="true">';
console.log($($.parseHTML(string)).attr("name")); //gives 'multi_select_frV6Yzed4dxzsotOvJ5cXg9Aa[]'

You can use this regex to retrieve that value:
var matches = /name="(.*)"\s/gi.exec(string);
console.log(matches[1]); // = "multi_select_frV6Yzed4dxzsotOvJ5cXg9Aa[]"
You would obviously need to make the code more robust to deal with cases where the attribute is not found.
You could also use jQuery:
console.log($(string).attr('name'));

See this working regex.
Here is the javascript code.
var re = /name="([^"]*)/g;
var str = '<select mltiple="" name="multi_select_frV6Yzed4dxzsotOvJ5cXg9Aa[]" aria-required="true">';
var m;
m = re.exec(str);
alert(m[1]);

Pattern match to get string between brackets

I am trying to find whatever string is in between the aggregate() and find(). Below is my code.
var str1 = 'aggregate([{$group:{_id:{state:"$state",city:"$city"},sum:{$sum:"$pop"}}},{$sort:{sum:1}},{$group:{_id:"$_id.state",smallestcity:{$first:"$_id.city"},smallest:{$first:"$sum"},largestcity:{$last:"$_id.city"},largest:{$last:"$sum"}}}])'
var str2 = 'find({awards:{$elemMatch:{award:"Turing Award",year:{$gt:1980}}}}).limit(0)'
var matchPharse = /((.*))/;
var result = str1.match(matchPharse);
console.log(result);
I am getting the result always the whole string instead of
[{$group:{_id:{state:"$state",city:"$city"},sum:{$sum:"$pop"}}},{$sort:{sum:1}},{$group:{_id:"$_id.state",smallestcity:{$first:"$_id.city"},smallest:{$first:"$sum"},largestcity:{$last:"$_id.city"},largest:{$last:"$sum"}}}]
I am searching for something like this

try this pattern instead:
var matchPharse = /((\[.*\]))/;

((\[.*?\]))
You Should use a non greedy expression.

Try the following RegEx:
var matchPharse= /\((.*)\)/g;
Matches any sequence between ().
This is a DEMO.
var str1 = 'aggregate([{$group:{_id:{state:"$state",city:"$city"},sum:{$sum:"$pop"}}},{$sort:{sum:1}},{$group:{_id:"$_id.state",smallestcity:{$first:"$_id.city"},smallest:{$first:"$sum"},largestcity:{$last:"$_id.city"},largest:{$last:"$sum"}}}])'
var str2 = 'find({awards:{$elemMatch:{award:"Turing Award",year:{$gt:1980}}}}).limit(0)'
var matchPharse = /\((.*)\)/;
var result = str1.match(matchPharse);
alert(result);

You just need to escape the outside parentheses. Try:
var matchPharse = /\((.*)\)/;
For just the content inside the parentheses use result[1]

Search through string with Javascript

Say I have a string like this:
jJKld-xxx-JKl122
Using javascript, how can I get on what's in-between the - characters? In others words, all I need to do is put whatever is xxx into a variable.
Thanks

If the string is always in that format, this will work:
var foo = 'jJKld-xxx-JKl122';
var bar = foo.split('-')[1]; // = xxx

just try it with this simple regex
var str = 'jJKld-xxx-JKl122';
var xxx = str.replace( /^[^\-]*-|-[^\-]*$/g, '' );

You can simply use the following regex to get the result
var myString = "jJKld-xxx-JKl122";
var myRegexp = /(?:^|\s*)-(.*?)-(?:^|\s*)/g;
var match = myRegexp.exec(myString);
alert(match[1]);
See the demo here

get particular string part in javascript

I have a javascript string like "firstHalf_0_0_0" or secondHalf_0_0_0". Now I want to get the string before the string "Half" from above both strings using javascript.Please help me.
Thanks.

var myString = "firstHalf_0_0_0";
var parts = myString.split("Half");
var thePart = parts[0];

var str = 'firstHalf_0_0_0',
part = str.match(/(\w+)Half/)[1];
alert(part); // Alerts "first"

var str = "firstHalf.....";
var index = str.indexOf("Half");
var substring = str.substr(0, index);
jsFiddle demo.

Using this you can get any particular part of string.
var str= 'your string';
var result = str.split('_')[0];

Working example here for your particular case.
http://jsfiddle.net/7kypu/3/
cheers!