javascript - Can regular expressions write glue matches (without using es6's y)?

<code>var str="abc"; 
var patt1=/\w/g;
document.write(str.match(patt1));</code>

Copy after login

Copy after login

In the above code, the matching result is ['a','b','c']

Is there a regular writing method that can make the matching result ['a','ab','abc','b','bc','c'], similar to the combination of high school mathematics

Reply content:

<code>var str="abc"; 
var patt1=/\w/g;
document.write(str.match(patt1));</code>

Copy after login

Copy after login

In the above code, the matching result is ['a','b','c']

Is there a regular writing method that can make the matching result ['a','ab','abc','b','bc','c'], similar to the combination of high school mathematics

Just use the combination algorithm~

python3

<code class="python">import itertools as itrs

s = "abc"
rslt = ','.join((','.join((''.join(tlp)for tlp in itrs.combinations(s,r)))
                                       for r in range(1,len(s)+1)))
print(rslt)</code>

<code>'a,b,c,ab,ac,bc,abc'
</code>

Keep it simple~

<code class="python">from itertools import chain, combinations as combs
chn_itr = chain.from_iterable
s = "abc"
print([''.join(x)for x in chn_itr(combs(s,r)for r in range(1,len(s)+1))])</code>

<code>['a', 'b', 'c', 'ab', 'ac', 'bc', 'abc']</code>

Consider the algorithm implementation, exhaustive js

<code>var str = "abc";
console.log(getStr(str))

function getStr(str) {
  var len = str.length;
  var i, j;
  var res = [];
  for (i = 0; i <= len; i++) {
    for (j = i + 1; j <= len; j++) {
      res.push(str.substr(i, j))
    }
  }
  return res;
}</code>