正则表达式用于首次出现

Question

I have string that looks like :

"test-file" : "abc.xml","test2-file":"abcd.xml","test3-file":"bcde.xml","test-file" : "def.xml"'

How can I create a regex that outputs an array like :

{abc.xml, def.xml} or {"test-file" : "abc.xml","test-file" : "def.xml"} 

that is only pairs with test-file before ‍‍ ':' .

I tried :

json.match(/"test-file" : "(.*)\.xml"/); 

but I am getting output:

0: "\\"test-file\\" : \\"abc.xml\\",\\"test2-file\\":\\"abcd.xml\\",\\"test3-file\\":\\"bcde.xml\\",\\"test-file\\" : \\"def.xml\\""
​ 1: "abc.xml\\",\\"test2-file\\":\\"abcd.xml\\",\\"test3-file\\":\\"bcde.xml\\",\\"test-file\\" : \\"def"

Answer 1

Store the value in a string and use split function

Example :

test_string='"test-file" : "abc.xml","test2-file":"abcd.xml","test3-file":"bcde.xml","test-file" : "def.xml"';
test_string.split(",");

It will split that string by , and store values in an array.

Answer 2

If all the key-value pairs you are looking for are

• on the same node or
• the same level

you should be fine using JSON directly.

I doubt that regex will be helpful when you have to deal with variable key names. There must be a criterion that allows you to distinguish the good keys from the bad keys.

If this criterion is the order, here is a sample built around Object.keys to access the values without knowing the actual name of the key. However, there are many other ways to do this .

 // Function to get the nth key from the object Object.prototype.getByIndex = function(index) { return this[Object.keys(this)[index]]; }; var json = { "config": { "files": [{ "name1": "test.xml"}, { "name2": "test2.xml" }] } }; $.each(json.config.files, function(i, v) { if (i !== 0) // or whatever is a "good" index return; //or if it is the content of the value the identifies a good value... if (v.getByIndex(0).indexOf(".xml") !== -1) { console.log(v); return; } }); 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script> 

If you do a lot of this JSON querying operations a JSON query language/library like JSONiq , JSPath , or jsonpath could be the right thing for you.

---

If your substring/key is always the same you can indeed make use of regex, eg

 const regex = /"test-file"\\s*:\\s*".*?\\.xml"/g; const str = `"test-file" : "abc.xml","test2-file":"abcd.xml","test3-file":"bcde.xml","test-file" : "def.xml"'`; let m; while ((m = regex.exec(str)) !== null) { // This is necessary to avoid infinite loops with zero-width matches if (m.index === regex.lastIndex) { regex.lastIndex++; } m.forEach((match, groupIndex) => { console.log(`Found match, group ${groupIndex}: ${match}`); }); }