Test if a sentence is matching a text declaration using regex

Question

I want to test if a sentence like type var1,var2,var3 is matching a text declaration or not.

So, I used the following code :

var text = "int a1,a2,a3",
     reg = /int ((([a-z_A-Z]+[0-9]*),)+)$/g;

if (reg.test(text)) console.log(true);
else console.log(false)

The problem is that this regular expression returns false on text that is supposed to be true.

Could someone help me find a good regular expression matching expressions as in the example above?

What about `int a,b,c,`, should it be true? Also, your regex does not allow `a2b2`. Is that what you really want? — Wiktor Stribiżew, Nov 20 '16 at 20:41
int a,b,c, should be false I have found a good solution /int ([a-zA-Z]+[0-9]*(,([a-zA-Z]+[0-9]*))*)$/g.test(str) — h3t1, Nov 20 '16 at 20:44
I see, so you accepted an answer that does not answer your question. There is also an issue with the modifier you are using with `RegExp#test()`. See http://stackoverflow.com/questions/1520800/why-regexp-with-global-flag-in-javascript-give-wrong-results — Wiktor Stribiżew, Nov 20 '16 at 20:46
because other answers doesn't work for me and that answer was the best — h3t1, Nov 20 '16 at 20:48
you just need learn how to ask... http://stackoverflow.com/help/how-to-ask — Hitmands, Nov 20 '16 at 20:52

score 2 · Answer 1 · answered Nov 20 '16 at 20:26

You have a couple of mistekes.

As you wrote, the last coma is required at the end of the line.
I suppose you also want to match int abc123 as correct string, so you need to include letter to other characters
Avoid using capturing groups for just testing strings.

const str = 'int a1,a2,a3';
const regex = /int (?:[a-zA-Z_](?:[a-zA-Z0-9_])*(?:\,|$))+/g

console.log(regex.test(str));

Ibrahim · Accepted Answer · 2016-11-20T21:57:09.007

1

You will need to add ? after the comma ,.

This token ? matches between zero and one.

Notice that the last number in your text a3 does not have , afterward.

int ((([a-z_A-Z]+[0-9]*),?)+)$

edited Nov 20 '16 at 21:57

answered Nov 20 '16 at 20:24

Ibrahim

2 Answers2