All strings located between the specified phrases

Question

All strings located between the specified phrases

I am attempting to extract strings that are located between two specific strings, but the output I am getting from using str.match is not what I anticipated:

var text = "first second1 third\nfirst second2 third\nfirst second3 third";
var middles = text.match(/first (.*?) third/g);
console.log(middles);  //this should be ["second1", "second2", "second3"]

However, the actual result looks like this:

["first second1 third", "first second2 third", "first second3 third"]

Is there a different approach I can take to only extract the middle strings for each occurrence?

javascript regex string substring match

Answer 1

Answer №1

According to the information provided in the RegExp.prototype.exec() documentation:

If your regular expression includes the "g" flag, you have the ability to use the exec method repeatedly to identify consecutive matches within the same string. In such cases, the search commences at the specific substring of str indicated by the lastIndex property of the regular expression (the test() function will also increment the lastIndex property).

Incorporating this concept into your situation:

var text = "first second1 third\nfirst second2 third\nfirst second3 third";
var middles = [], md, regex = /first (.*?) third/g;

while( md = regex.exec(text) ) { middles.push(md[1]); }

middles // ["second1", "second2", "second3"]

Answer 2

According to the information provided in the RegExp.prototype.exec() documentation:

If your regular expression includes the "g" flag, you have the ability to use the exec method repeatedly to identify consecutive matches within the same string. In such cases, the search commences at the specific substring of str indicated by the lastIndex property of the regular expression (the test() function will also increment the lastIndex property).

Incorporating this concept into your situation:

var text = "first second1 third\nfirst second2 third\nfirst second3 third";
var middles = [], md, regex = /first (.*?) third/g;

while( md = regex.exec(text) ) { middles.push(md[1]); }

middles // ["second1", "second2", "second3"]

All strings located between the specified phrases

Answer №1

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