Check if substring is present in another string, regex

Question

I have two strings:

var first = "913 DE 6D 3T 222"
var second = "913 DE 3T 222"

I want to check if second is present in first, preferably with regex. The problem is that indexOf or includes returns that second is not present in first, which is wrong (only 6D is the difference):

first.indexOf(second)
-1

first.includes(second)
false

http://stackoverflow.com/questions/1789945/how-to-check-if-one-string-contains-another-substring-in-javascript — AshBringer, Dec 06 '16 at 08:30
maybe you should split your 2nd string and check if the values are contained in string 1? and second **is not** completely present in first, thats why the methods work correctly — XtremeBaumer, Dec 06 '16 at 08:30
@RomanPerekhrest would be great with regex solution. and order of words is not sufficient to take in account, only if all characters or numbers are present from one string in another — user1665355, Dec 06 '16 at 08:46

Pranav C Balan · Accepted Answer · 2016-12-06T09:28:35.003

Use String#split and Array#every methods.

var first = "913 DE 6D 3T 222";
var second = "913 DE 3T 222";

console.log(
  second
  // split the string by space
  .split(' ')
  // check all strings are contains in the first
  .every(function(v) {
    return first.indexOf(v) > -1;

    // if  you want exact word match then use regex with word
    // boundary although you need to escape any symbols which
    // have special meaning in regex but in your case I think all are 
    // alphanumeric char so which is not necessary

    // return (new RegExp('\\b' + v + '\\b')).test(first);
  })
)

FYI : For older browser check polyfill option of every method.

@user1665355 : check with regex option added in the comment – Pranav C Balan Dec 06 '16 at 09:02 — Pranav C Balan, Dec 06 '16 at 09:02

Mihai Alexandru-Ionut · Answer 2 · 2016-12-06T09:08:33.790

1

This is a more elegant solution.

First of all, I'm using map function. In our case it is returning an array something like this:

[true,true,true,true]. Then, using reduce function and logical operators we will obtain one single value. If array containes at least one false value, then final result will be false.

var first = "913 DE 6D 3TT 222";
var second = "913 DE 3T 222";
console.log(second.split(' ').map(function(item){
    return first.includes(item);
}).reduce(function(curr,prev){
    return curr && prev;
}));

edited Dec 06 '16 at 09:08

answered Dec 06 '16 at 08:33

Mihai Alexandru-Ionut

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@Alexandru-Iounut Mihai This will check if all characters and numbers are present in first from second? – user1665355 Dec 06 '16 at 08:53
@user1665355, yes, I used a logical Operators – Mihai Alexandru-Ionut Dec 06 '16 at 08:53
that returns false if first string is `var first = "913 DE 6D 3TT 222".split(' ');`, note one more `T` in `3TT`. Should be true still, because all characters in second still present in first. – user1665355 Dec 06 '16 at 08:57

score 0 · Answer 3 · answered Dec 06 '16 at 09:03

The solution using String.match() function and a specific regex pattern:

I've change the first string to make a more complex case, duplicate DE value added.

var first = "913 DE 6D 3T 222 DE",
    second = "913 DE 3T 222",
    count = second.split(' ').length;

var contained = (count == first.match(new RegExp('(' + second.replace(/\s/g, "|") + ')(?!.*\\1)', "gi")).length);
console.log(contained);

(?!.*\1) - is negative lookahead assertion to avoid duplicate matches

Check if substring is present in another string, regex

3 Answers3