How to loop all the elements that match the regex?
JavascriptRegexJavascript Problem Overview
Here is the case: I want to find the elements which match the regex...
> targetText = "SomeT1extSomeT2extSomeT3extSomeT4extSomeT5extSomeT6ext"
and I use the regex in javascript like this
reg = new RegExp(/e(.*?)e/g);
var result = reg.exec(targetText);
and I only get the first one, but not the follow.... I can get the T1 only, but not T2, T3 ... ...
Javascript Solutions
Solution 1 - Javascript
var reg = /e(.*?)e/g;
var result;
while((result = reg.exec(targetText)) !== null) {
doSomethingWith(result);
}
Solution 2 - Javascript
Three approaches depending on what you want to do with it:
-
Loop through each match:
.match
targetText.match(/e(.*?)e/g).forEach((element) => { // Do something with each element });
-
Loop through and replace each match on the fly:
.replace
const newTargetText = targetText.replace(/e(.*?)e/g, (match, $1) => { // Return the replacement leveraging the parameters. });
-
Loop through and do something on the fly:
.exec
const regex = /e(.*?)e/g; // Must be declared outside the while expression, // and must include the global "g" flag. let result; while(result = regex.exec(targetText)) { // Do something with result[0]. }
Solution 3 - Javascript
Try using match() on the string instead of exec(), though you could loop with exec as well. Match should give you the all the matches at one go. I think you can omit the global specifier as well.
reg = new RegExp(/e(.*?)e/);
var matches = targetText.match(reg);
Solution 4 - Javascript
I kept getting infinite loops while following the advice above, for example:
var reg = /e(.*?)e/g;
var result;
while((result = reg.exec(targetText)) !== null) {
doSomethingWith(result);
}
The object that was assigned to result
each time was:
["", "", index: 50, input: "target text", groups: undefined]
So in my case I edited the above code to:
const reg = /e(.*?)e/g;
let result = reg.exec(targetText);
while(result[0] !== "") {
doSomethingWith(result);
result = reg.exec(targetText);
}
Solution 5 - Javascript
targetText = "SomeT1extSomeT2extSomeT3extSomeT4extSomeT5extSomeT6ext"
reg = new RegExp(/e(.*?)e/g);
var result;
while (result = reg.exec(targetText))
{
...
}
Solution 6 - Javascript
You could also use the String.replace method to loop through all elements.
result = [];
// Just get all numbers
"SomeT1extSomeT2extSomeT3ext".replace(/(\d+?)/g, function(wholeMatch, num) {
// act here or after the loop...
console.log(result.push(num));
return wholeMatch;
});
console.log(result); // ['1', '2', '3']
Greetings
Solution 7 - Javascript
I did this in a console session (Chrome).
> let reg = /[aeiou]/g;
undefined
> let text = "autoeciously";
undefined
> matches = text.matches(reg);
(7) ["a", "u", "o", "e", "i", "o", "u"]
> matches.forEach(x =>console.log(x));
a
u
o
e
i
o
u
Solution 8 - Javascript
I was actually dealing with this issue. I prefer Lambda functions for about everything.
reg = /e(.*?)e/gm;
targetText.match(reg).forEach(element => console.log(element));